QUESTIONS WITH ANSWERS 
ON PUMPS AND PUMPING 
MACHINERY 



W. H. WAKEMAN 



THE JOSEPH O. BRANCH PUBLISHING CO. 




(toss T33 60 
Book .11) 2. 



CpfyrightN?. 



COFVniCHT DEPOSIT. 



QUESTIONS AND ANSWERS 



ON 



Pumps and Pumping 
Machinery 



BY 

Wv H. WAKEMAN 

AUTHOR OF 

Engineering Practice and Theory, Modern Examinations of 

Steam Engineers, The Practical Guide 

for Firemen, Etc. 



▲ ▲ A 



CHICAGO 

The Joseph G. Branch Publishing Company 
1912 






Copyright, 1912, by 
Joseph G. Branch 



/?- 31M 



THE HENRY 0. SHEPARD CO., PRINTERS, CHICAGO. 



V-* 



©CI.A343153 
*0 f 



PREFACE 

A working knowledge of the various kinds of pump- 
ing machinery required by the widely different condi- 
tions under which such machinery is used is an essen- 
tial part of the education of a competent steam engi- 
neer. Such knowledge does not necessarily include an 
intimate acquaintance with each separate part of 
every machine, but it is an excellent plan to have a 
general idea of the kind of a machine that will give 
best results under stated conditions. 

For illustration, a given kind of pump would prove 
efficient and durable when raising pure water, but it 
might not be suitable for water containing sand and 
other foreign matter. If used in such service it would 
soon become worn out and inefficient. On the other 
hand, if a pump that was designed and built for these 
conditions had been selected and installed, the result 
would have been much more satisfactory. 

One object sought in offering this book to engi- 
neers and others interested is to show such a variety 
of pumps that one can be selected for every place and 
condition under which a machine of this kind can be 
used. For this purpose, only a general outline of each 
is required. 

Sometimes an engineer decides that it is useless for 
him to become thoroughly well posted on pumping 
machinery (or any other part of steam engineering), 
because his employer never consults him about the 



PREFACE. 

purchase of new equipment, but such a conclusion is 
inconsistent, because if he remains ignorant on these 
subjects he never can be successfully consulted, and 
soon he is not even asked for his opinion. 

The machines illustrated are standard goods in their 
several lines, as they were selected from lists given 
out by prominent manufacturers of these goods. 

That this book may prove valuable to those men 
for whom it was written is the sincere wish of 

THE AUTHOR. 
New Haven, Conn., 
November, 1912. 



LIST OF ILLUSTRATIONS. 

ILLUSTRATION PAGE 

1 . Vertical Direct-connected Pump 3 

2. Horizontal Direct-connected Pump 5 

3. Horizontal Pump on Portable Boiler 7 

4. Single-acting Power Pump . , 9 

5. Double-acting Power Pump 11 

6. Geared Power Pump 13 

7. Belted Motor-driven Pump 15 

8. Geared Motor-driven Pump 17 

9. Triplex Power Pump 19 

10. Horizontal Engine Driving Power Pump. . . 21 

11. Vertical Engine Driving Power Pump 22 

12. Mercurial Barometer . . . . 24 

13. Elevated Power Pump 26 

14. Motor-driven Elevated Pump 28 

15. Deep-well Pump, Plunger Ascending 30 

16. Deep-well Pump, Plunger Descending 31 

17. Single Horizontal Power Pump 33 

18. Pot Valve Power Pump 35 

19. Triple-geared Power Pump 37 

20. Motor-driven Horizontal Pump 38 

21. Horizontal Double Power Pump 41 

22. Horizontal Triple Power Pump 42 

23. Motor-driven Portable Pump 44 

24. Single Vacuum Power Pump 45 

25. Double Vacuum Power Pump 46 

26. Power Force Pump 47 

27. Motor-driven Force Pump 49 

28. Geared Rotary Pump 50 

29. Elliptical Geared Rotary Pump 52 

30. Rotary Pump, Fitted with Cams 53 

31. Rotary Pump, Fitted with Two Impellers.. 55 

32. Rotary Pump, Fitted with Two Triple Im- 

pellers 56 

v 



QUESTIONS AXD ANSWERS ON 

PAGE 

33. Single Rotary Tump 58 

34. Single-cam Rotary Pump 60 

3?. Revolving Cylinder Rotary Pump 61 

36. Single Suction Centrifugal Pump, Side Ele- 

vation 62 

37. Single Suction Centrifugal Pump, End Ele- 

vation 63 

38. Double Suction Centrifugal Pump, End Ele- 

vation 64 

39. Single Stage Horizontal Centrifugal Power 

Pump 66 

40. Single Stage Vertical Centrifugal Power 

Pump 67 

41. Motor-driven Single Conoidal Pump 69 

42. Motor-driven Twin Conoidal Pump 70 

43. Engine-driven Two-stage Turbine Pump ... 73 

44. Power-driven Quadruple Turbine Pump .... 74 

45. Motor-driven Quadruple Turbine Pump. ... 76 

46. Sectional Elevation of Quadruple Turbine 

Pump 77 

47. Vertical Turbine Waterworks Pump 78 

48. Vertical Two-stage Turbine Waterworks 

Pump 79 

49. Vertical Four-stage Turbine Pump 80 

50. Sectional Four-stage Turbine Pump 81 

51. Fly-wheel Pump, Crank-shaft Next to the 

Water Cylinder 85 

52. Fly-wheel Pump, Crank-shaft Next to the 

Steam Cylinder 87 

53. Fly-wheel Pump, Scotch Yoke Gear 88 

54. Fly-wheel Pump, Crank-shaft Between the 

Cylinders 90 

55. Fly-wheel Pump, Throttling Governor De- 

sign 92 

56. Fly-w r heel Pump, Vertical Type, with Scotch 

Yoke 93 

57. Fly-wheel Pump, Tandem Type 95 

vi 



PUMPS AND PUMPING MACHINERY. 

PAGE 

58. Fly-wheel Pump, Double Air Pump, Vertical 

Type 96 

59. Fly-wheel Pump, Double-acting, Vertical 

Type 97 

60. Fly-wheel Pump, Vertical Duplex Air Ex- 

hauster 98 

61. Original Direct-acting Pump 101 

62. B Valve Direct-acting Pump 102 

63. Pistons for 14 by 7 by 12 inch Pump 103 

64. Pistons for 10 by 10 by 12 inch Pump 103 

65. Pistons for 8 by 14 by 12 inch Pump 105 

66. Pistons for 14 by 2]/ 2 by 12 inch Pump 105 

67. Submerged Piston Pump 106 

68. Plunger and Ring Pump 108 

69. Outside Center Packed Plunger Pump 109 

70. Outside End Packed Plunger Pump Ill 

71. Long Stroke Pump 112 

72. Long Stroke and Long Body Pump 115 

73. Sectionalized Mountain Pump 116 

74. Protected Mine Pump 117 

75. Hydraulic Pump 119 

76. Ammonia Direct-acting Pump 120 

77. Steam-heating Pump 121 

78. Direct-acting Vacuum Pump 122 

79. Magma Pump 124 

80. Direct-acting Blowing Engine 125 

81. Double-deck Three-cylinder Pump 128 

82. Three-cylinder Double-vacuum Pump 130 

83. Tail Pump 131 

84. Water and Vacuum Pump 132 

85. Air and Circulating Pump 133 

86. Cold and Hot Water Pump 134 

87. Salt Water and Boiler Feed Pump 136 

88. Combined Air Compressor and Boiler Feeder 138 

89. Combined Vacuum and Circulating Pump. . . 139 

90. Combined Wet and Dry Vacuum Pump. . . . 140 

91. Sectional Jet Condenser and Air Pump 142 

vii 



PUMPS AND PUMPING MACHINERY. 

PAGE 

92. Jet Condenser with Vacuum Breaker Pump. 145 

93. Jet Condenser for Vertical Marine Engine. . 146 

94. Vertical Double Air Pump 147 

95. Four-cylinder Air Pump 148 

96. Vertical Condenser 150 

97. Condenser with Vertical Pumps 152 

98. Vertical Four-cylinder Combined Pumps... 153 

99. Horizontal Four-cylinder Combined Pumps. 155 

100. Modern Steam Plant for Making Ice 156 

101. Horizontal Pump and Vertical Receiver. ... 158 

102. Horizontal Pump and Receiver 159 

103. Receiver Above Horizontal Pump 161 

104. End View of Pump and Receiver 162 

105. Duplex Pump and Elevated Receiver 163 

106. Two Pumps and One Receiver 164 

107. Motor-driven Pump and Vertical Receiver. . 167 

108. Portable Pumping Outfit 168 

109. Semi-portable Pumping Outfit 169 

110. Locomotive Boiler and Duplex Pump 170 

111. Single Vertical Direct-acting Pump 172 

112. Vertical Bulkhead Pump 173 

113. Vertical Duplex Direct-acting Pump 175 

114. Vertical Sinking Pump 176 

115. Vertical Sinking Condensing Pump 177 

116. Vertical Duplex Sinking Pump 179 

117. Wrecking Pump 180 

118. Vertical Ammonia Pump 182 

119. Shell of Direct Steam Pump 183 

120. Engine for Direct Steam Pump 185 



Vlll 



Questions and Answers 



ON 



Pumps and Pumping Machinery 



1. Q. What is a pump? 

A. A device for transferring liquids, fluids or gases 
from a lower to a higher level, against pressure due 
to friction, the head or height attained, or the process 
of forcing the moving material into a boiler or a closed 
tank. 

2. Q. What are the objects sought in the design 
and construction of the various kinds of pumps? 

A. Simplicity of design, resulting in low first cost, 
ample strength without excessive weight, reliability 
in operation, reduction of friction to the lowest prac- 
tical point and economy in the use of power. 

3. Q. Explain the advantages of simple design? 
A. Simplicity is desired by the owner because less 

capital is required for machinery to secure desired 
results, and by the engineer because there are fewer 
parts to take care of, and repairs can be made with 
less delay to operation of the plant. 

4. Q. While the necessity for ample strength is 
plain, why should excessive weight be avoided? 

A. Because it increases the cost of moving and 
locating these machines, especially portable plants 
which are extensively used in construction work. 

5. Q. Explain the advantages of reliability in 
operation. 



2 QUESTIONS AND ANSWERS ON 

A. It enables the engineer to start his pumping 
machinery promptly when required for important 
work, and reduces the risk of failure to continue the 
pumping process during the temporary absence of the 
attendant. Such failures are frequently both danger- 
ous and expensive. 

6. Q. Why should friction be reduced to the low- 
est practical point? 

A. Because excessive friction results in unneces- 
sary wear of machinery and causes more or less waste 
of power. 

7. Q. Why is the word " practical " used in this 
connection instead of "possible"? 

A. It shows that it is possible to overlook more 
important features, where too much attention is given 
to freedom from friction. 

8. Q. Why should an engineer select pumping 
machinery that can be operated with the least cost 
for power, when he is not required to pay the fuel 
bills? 

A. Every engineer should work for the best in- 
terests of his employer. This includes the economi- 
cal use of fuel, oil, packing, etc. A good record along 
this line entitles an engineer to a good salary and fair 
treatment otherwise. 

9. Q. What is the simplest form of pump for 
boiler feeding? 

A. The direct-connected power pump, as illus- 
trated in Fig. 1. In this case a vertical engine is 
shown, but the same kind of pump is used under other 
conditions. 

10. Q. Explain its operation. 

A. A disk, a plain crank or an eccentric is placed 
on the outer end of the crank shaft. To the crank pin 
is attached a connecting rod, which changes the cir- 
cular motion of the crank pin into a reciprocating 
motion at the pump plunger. When this plunger 



PUMPS AND PUMPING MACHINERY. 3 




FIG./ 



4 QUESTIONS AND ANSWERS ON 

moves upward it draws water in through the left- 
hand check valve, and when it moves downward this 
water is forced out through the right-hand check 
valve. 

11. Q. What other advantage is gained by its 
use? 

A. It is very economical in the use of power 
because it is driven directly from the main engine in 
which steam is used expansively. 

12. Q. What are the disadvantages of this pump? 
A. It can not be used when the engine is shut 

down, therefore, if it becomes necessary to stop it 
with heavy fires in the furnaces, the process of boiler 
feeding can not be continued for the purpose of pre- 
venting dangerous rise in steam pressure. The speed 
of pump can not be varied to suit changes in the 
amount of steam used. 

13. Q. Is it possible to vary the amount of water 
delivered by such a pump ? 

A. Yes; by throttling the supply of water. The 
delivery valve should always be wide open while the 
pump is in operation, as otherwise the feed pipe may 
be burst by excessive pressure. This is sure to hap- 
pen if this valve is not opened before the engine is 
started. Particular attention is called to this point 
because many accidents have happened from this 
cause. 

14. Q. Is this a single-acting or double-acting 
pump? 

A. It is single-acting, because water is drawn in 
on one stroke and sent out during the next. More 
or less vibration results from this action, and shocks 
are usually felt throughout the pipe line, unless spe- 
cial care is taken to locate one or more air chambers 
where the air in them will act as a cushion for the 
water. It is not advisable to use such a pump on a 
high-speed engine on this account. 



PUMPS AND PUMPING MACHINERY. 5 




6 QUESTIONS AND ANSWERS ON 

15. Q. Can this type of pump be used on a hori- 
zontal engine with equally good results? 

A. Yes; a driving crank can be located on the 
outer end of a horizontal engine shaft, or the pump 
may be placed in a horizontal position and connected 
directly to the crosshead, as shown in Fig. 2. The 
principle of operation is the same, with equal advan- 
tages and disadvantages. 

16. Q. Is this kind of pump used on portable 
engines ? 

A. It was formerly used extensively in this serv- 
ice with satisfactory results, as its simple design and 
strong construction rendered it reliable in practice 
where unfavorable conditions would cause others to 
fail. See Fig. 3. (Injectors are now used on such out- 
fits.) 

17. Q. Explain the operation in this case? 

A. The pump is attached to the crosshead at 2. 
It draws water in through the pipe 3, and shocks and 
jars are prevented by the air chamber 4. It is then 
forced through the heater 5, where exhaust steam 
raises its temperature, after which it goes through 6 
into the boiler. 

18. Q. Would it be better to draw water through 
the heater under no pressure, and then force it directly 
into the boiler? 

A. It would not, because it is always better to 
pump cold water and heat it after it has passed the 
pump. 

19. Q. Can hot water be pumped without trou- 
ble? 

A. Yes ; but the same pump will deliver a greater 
volume of water at a low temperature, or at least this 
is the result so far as the boiler is concerned. If a 
cubic foot of very cold water passes through a pump 
it will fill more than a cubic foot after it is heated to 



PUMPS AND PUMPING MACHINERY. 7 

a high temperature, hence it occupies more space in 
the boiler owing to expansion by heat. 

20. Q. If a direct-connected pump fails to deliver 
its full capacity to the boiler, where would you look 
for the cause of trouble ? 




FfG 3. 

A. The supply of water may be less than formerly, 
or the suction pipe may be partly choked with sticks 
or leaves. Even a very small piece of wood, if caught 
under the disk of a check valve, will prevent it from 
seating perfectly. This will allow water to churn 
back and forth, instead of passing into the boiler. The 
water piston may be worn enough to let water pass 
by it, or the feed pipe may be nearly closed by scale 



8 QUESTIONS AND ANSWERS ON 

where it enters the boiler. Examine all of these parts 
until the defect is discovered. 

21. Q. What precaution should be taken to pre- 
vent leaves, etc., from being drawn into a pump, where 
water is drawn from a barrel? 

A. A fine strainer should be placed on the end of 
the suction pipe. The actual area of openings in this 
strainer ought to be at least double the area of the 
pipe, so that when it is partly choked by foreign mat- 
ter, enough water can pass to supply the pump. 

22. Q. How is the delivery of water to such a 
barrel regulated, where it flows in from a higher 
source ? 

A. By a balanced valve, operated by a float that 
closes the valve if the quantity increases, or opens it 
if the water level falls. 

23. Q. Is it good policy to provide such a regu- 
lator when the fireman has time enough to regulate 
the supply by hand? 

A. It is; because mechanical regulation is always 
superior to hand service, and at the same time it allows 
the fireman to give attention to other duties, thus 
proving a good investment. 

24. Q. Name another very simple and economi- 
cal pump. 

A. The belt-driven power pump. See Fig. 4. 

25. Q. How is it driven? 

A. By a belt that runs a pulley on a suitable 
crank shaft. The crank, by means of a connecting 
rod, gives vertical motion to a plunger that draws in 
water on the upward, and discharges it on the down- 
ward stroke, through the check valve shown. 

26. Q. Is it necessary to run such a pump as 
long as the engine is in operation? 

A. No; it is provided with a tight and loose pul- 
ley, by means of which it can be started and stopped 
at pleasure. 



' PUMPS AND PUMPING MACHINERY. 9 




Fie. 4. 



10 QUESTIONS AND ANSWERS ON 

27. Q. Is it good practice to run a pump fast, 
fill up a boiler quickly, and then shut it down until 
the water level falls to one gauge? 

A. It is not. There is always danger of running 
the pump too long, thus raising the water level until 
the engine is wrecked, or allowing it to stand until 
the boiler is burned for lack of water. 

28. Q. What other disadvantage results? 

A. With a high water level the steam space in the 
boiler is reduced, hence there is a smaller volume to 
draw from, and as more water is heated and steam 
that is formed in the lower parts must pass up through 
this water, more fuel is required to produce an equal 
amount of steam. Unequal expansion and contraction 
is increased by great changes in the water level. 

29. Q. How can the amount of water delivered 
be regulated to suit the quantity used, thus maintain- 
ing a nearly constant w&ter level? 

A. By connecting a small pipe from the discharge 
to the suction pipe, called a by-pass. By a valve in this 
pipe the amount circulated is regulated, and as the 
remainder is delivered to the boiler the desired result 
is secured. 

30. Q. Describe another plan for regulating the 
supply. 

A. A countershaft fitted with a cone pulley may 
be used, when, by shifting the belt, three or four 
changes of speed can be secured. 

31. Q. If the full capacity of the pump shown in 
Fig. 4 is not sufficient, how can a larger supply be 
secured, using the same pump? 

A. By putting a larger pulley on the driving shaft 
and running the pump at a higher speed. 

32. Q. Is this always practicable? 

A. No; the pump may already be running as fast 
as safety will permit. 

33. Q. How can this point be determined? 



PUMPS AND PUMPING MACHINERY. 11 

A. By the good judgment of the engineer in 
charge. 

34. Q. Give another plan for securing more 
water. 

A. If a larger pump is not available, another 
crank can be put on the opposite end of this shaft 
and another plunger operated by it. 




Fie. 5". 



35. Q. Is it possible to double the capacity of a 
belt-driven power pump on the same floor space with- 
out increasing the size of feed pipe? 

A. Yes ; by adopting the double-acting power 
pump illustrated in Fig. 5. 



12 QUESTIONS AND ANSWERS ON 

36. Q. How is it possible for this pump to de- 
liver double the capacity of a single-acting pump of 
the same diameter, stroke and speed? 

A. Because it delivers a nearly continuous stream, 
while the other discharges on the downward stroke 
only, or during a trifle less than one-half of one revo- 
lution of the crank shaft. 

37. Q. How is this result secured? 

A. During the upward stroke of plunger water 
is drawn in through the lower left-hand check valve, 
and discharged through the upper right-hand valve. 
While the plunger is moving downward, water is 
drawn in through the upper left-hand check valve, 
and discharged through the lower right-hand valve. 

38. 0. What are the disadvantages of this pump? 
A. There are none, except those that apply to a 

single-acting pump, as above mentioned. 

39. Q. If a large gear is used instead of the pul- 
ley, and another shaft added as shown in Fig. 6, will 
the pump require less power? 

A. No; the power required to drive a pump is 
represented by the quantity of water delivered against 
a given pressure, plus the friction of the pump itself. 
As gears always cause friction, a pump is no excep- 
tion to the general rule. 

40. Q. Which requires the wider belt, a geared 
pump, or one without gears? 

A. The latter. 

41. Q. How is that possible, if the former re- 
quires more power? 

A. A geared pump can be run with a compara- 
tively narrow belt, but it must run at a high speed to 
secure a given number of strokes per minute. Speed 
absorbs power fast, and this accounts for the differ- 
ence. 

42. Q. Which kind is the most desirable? 



PUMPS AND PUMPING MACHINERY. 13 




FIG.6. 



14 QUESTIONS AND ANSWERS ON 

A. The geared pump, as it is nearer positive in 
practice, delivering water easily against high pres- 
sures. 

43. Q. Which is more suitable for pumping water 
into elevated tanks? 

A. For ordinary elevations, say 100 feet or less, 
the pump without gears may be used to good advan- 
tage. For greater heights the geared type is recom- 
mended. 

44. Q. How is the pressure due to a given height 
calculated? 

A. By multiplying the height in feet by .434; for 
100 feet this gives 43.4 pounds, but more must be 
added for friction. 

45. Q. How much should be added? 

A. For good conditions it may be as low as ten 
per cent, while for unfavorable places it may be fifty 
per cent or more. 

46. Q. What constitutes favorable conditions? 
A. Large pipes and few ells in them. Long-sweep 

ells, or in many cases forty-five degree ells should be 
used. 

47. Q. Why do these give better results than 
ordinary ells? 

A. Because sharp turns in water pipes change the 
direction of flow suddenly, thus tending to reduce the 
speed of water, and the pump has to restore the lost 
speed. 

48. Q. Should the discharge pipe enter the bot- 
tom of a tank, or ought it to pass over the top? 

A. It should enter the side, near the bottom. 

49. Q. What are the advantages of this arrange- 
ment? 

A. The pump delivers against pressure due to 
height of water in the tank only, and the delivery pipe 
may also be used to draw water from the tank, ren- 
dering another pipe unnecessary. 



PUMPS AND PUMPING MACHINERY. 15 



50. Q. How would you control the supply in 
such a case? 

A. A float in the tank should be provided with 
suitable connection whereby the driving belt will be 
shifted onto a loose pulley when the tank is full. 

51. Q. Describe a motor-driven, belted-power 
pump. 




FIG. 7" 

A. It consists of any type of power pump, driven 
by an electric motor by means of a belt. See Fig. 7. 
52. Q. Is a belt-tightener necessary in this case? 
A. Yes. 



16 QUESTIONS AND ANSWERS ON 

53. Q. Why? 

A. Because any ordinary belt will stretch more or 
less, thus rendering it incapable of transmitting the 
power necessary to drive the pump. An adjustable 
tightener is then required to restore the lost tension. 

54. Q. What causes the belt to stretch? 

A. A new belt will stretch until some of the nat- 
ural elasticity is taken out of it. Afterward it will 
stretch and contract as atmospheric conditions change, 
unless prevented by some special process of manufac- 
ture. 

55. Q. Why not use lacing and then cut out a 
piece of belt when it becomes slack? 

A. Because it would cause delay when the pump 
is required for constant service. 

56. Q. Is there another reason for not using 
lacing? 

A. Yes. It is a source of weakness, causing a 
belt to break when it is wanted for regular use. 

57. Q. Is it necessary to use a vertical pump? 
A. No, but this type is frequently used. 

58. Q. What are the advantages of such a com- 
bination ? 

A. It can be located in the most convenient posi- 
tion, regardless of line shafting, and the speed can be 
varied at pleasure to suit changing conditions. 

59. Q. Give another advantage. 

A. It is nearly noiseless in operation, hence gives 
satisfactory results in hotels, schools, etc., where any 
noise is objectionable. 

60. Q. What is a motor-driven, geared, power 
pump? 

A. Any type of pump to which power is supplied 
by an electric motor, by means of suitable gears. See 
Fig. 8. 

61. Q. What is the advantage of this form? 



PUMPS AND PUMPING MACHINERY. 17 



A. It provides positive means for transmitting the 
necessary power, as gears can not slip. 

62. Q. What are its disadvantages? 

A. It is noisy unless fitted with rawhide pinions. 
The fact that it gives positive motion is a disadvantage 
under certain conditions, for if a discharge valve is left 
closed when such a pump is started, something may 
burst, while a belt would probably run off from the 
pulleys. 




no.a 

63. Q. Is it economical in the use of power? 

A. Not especially, but it is convenient and this 
warrants its use, because the total amount of power 
used to drive it is comparatively small. 



18 QUESTIONS AND ANSWERS ON 

64. Q. As no shafting and belting are required, 
why is it not economical in the use of power? 

A. When a steam engine is used to drive a gen- 
erator, there is loss by friction, also in converting 
mechanical into electrical energy. The current gener- 
ated is used to drive a motor, thus restoring the 
mechanical energy and there is more loss by friction. 
These losses are usually equal to power lost in driving 
countershafts. 

65. Q. Describe another plan for driving a power 
pump. 

A. A cut-off coupling is located on the end of a 
suitable shaft, and this connects with the pump shaft 
as shown in Fig. 9. 

66. Q. What are the advantages of this design? 
A. Economy in power consumed, and convenience 

of operation, as it can be started and stopped at pleas- 
ure. 

67. Q. Are power pumps generally of the piston 
or the plunger type? 

A. Vertical pumps are nearly always of the 
plunger type. 

68. O. Describe a plunger. 

A. It is a cylinder, closed at one end and turned 
smooth on the outside. 

69. Q. How is it driven? 

A. By means of a wrist-pin passing through the 
plunger, to which a connecting rod is fastened. 

70. Q. What precautions should be taken when 
packing a plunger? 

A. If square packing is used it should completely 
fill the space provided for it, the rings ought to be cut 
short enough to provide an open space of about one- 
third inch between the ends, and the joints must be 
" broken," thus preventing two of them from coming 
together. 



PUMPS AND PUMPING MACHINERY. 19 

71. Q. Why must it completely fill the space? 

A. To prevent the necessity of screwing down the 
stuffing-box nuts too hard, in an effort to expand the 
packing. 




rie.9 



72. Q. If packing is loose when dry, will it not 
swell enough when wet to fill the space ? 

A. Some kinds will swell to a limited extent, but 
this quality should not be depended on, unless the 
engineer has found by experience that the desired 
results will be secured. 

73. Q. Why should an open space be left be- 
tween the ends of rings ? 

A. To allow for expansion caused by moisture. 



20 QUESTIONS AND ANSWERS ON 

74. O. What harm can result from expansion? 
A. The packing will bind on the plunger, causing 

excessive friction and loss of power. The plunger 
may be scored in the process. 

75. Q. How should this packing be treated? 

A. It ought to be soaked in water of about the 
same temperature of the water that is to be pumped. 

76. Q. Why? 

A. In order to expand it before it is used. 

77 . Q. If electric current is not available to drive 
a power pump, and no shaft is near at hand, how could 
the pump be driven? 

A. By a gas, or a gasoline engine, as shown in 
Fig. 10. 

78. Q. Is it proper to connect these machines 
rigidly? 

A. No, a friction clutch should be installed. 

79. Q. What is the advantage of this arrange- 
ment? 

A. As such an engine is usually started by hand, 
by disconnecting the pump the load is removed. When 
the engine is brought up to speed, the clutch may be 
thrown in slowly. 

80. Q. Can the soeed be regulated to meet vary- 
ing requirements? 

A. Yes, within reasonable limits. 

81. Q. Is this device economical in the cost of 
power? 

A. Yes. It is claimed that the gasoline engine is 
more economical than the steam engine. 

82. Q. What are the advantages of a vertical 
engine for the service as illustrated in Fig. 11? 

A. There are none, except a possible reduction of 
the friction load. Less floor-space is necessary, but 
that is not important in a large majority of cases. 



PUMPS AND PUMPING MACHINERY. 21 




22 



QUESTIONS AND ANSWERS ON 



83. Q. Are not gasoline engines undesirable for 
driving boiler feeders, on account of possible failure to 
operate steadily? 

A. The gasoline engine will not stand as much 
abuse as the steam engine, but with good care and 
management it should prove reliable in practice. 

84. Q. Where is a pumping outfit of this kind 
superior to any other? 

A. Where water is to be raised into an elevated 
tank, at considerable distance from the main boiler 
plant, with no electric current available to drive a 
motor. 




FIG.II 



85. Q. How high will a pump lift water? 

A. It should not be more than 25 feet above the 
surface, and this should be taken when the water is 
low, if conditions cause it to vary in height. If it is 20 
feet it will work better. 

86. Q. Why could it not be made 35 or 40 feet? 



PUMPS AND PUMPING MACHINERY. 23 

A. Because pressure or weight of the atmosphere 
is the real factor in determining this point. If all air 
be removed from the suction pipe of pump, water will 
rise in it high enough to balance the weight of air rest- 
ing on the outer water surface, but no higher. 

87. Q. Should this height be measured from the 
water surface, or from the bottom end of suction pipe ? 

A. From the water level in the suction pipe. 

88. Q. How is the height to which water can be 
raised by a pump determined in advance of actual 
trial? 

A. By use of a barometer. 

89. Q. Explain the design and construction of a 
barometer. 

A. It consists of a glass tube, the bore of which 
is of equal diameter throughout its entire length. It 
is not less than 36 inches long and one end is air- 
tight. The other end is inserted in mercury, as shown 
in Fig. 12. As a perfect vacuum is formed above the 
mercury, the column is supported by pressure of the 
atmosphere on the outer surface. 

90. Q. How does this illustrate the action of a 
pump? 

A. When a pump is used the suction pipe illus- 
trates the glass tube, while water is raised instead of 
mercury. 

91. Q. Describe the principle involved in the 
operation of a mercurial barometer. 

A. Weight of the atmosphere supports the mer- 
cury, hence the height of it varies with the weight of 
air. 

92. Q. What causes changes in the weight of the 
atmosphere? 

A. Variations in the amount of moisture it con- 
tains. 

93. Q. What is this commonly called? 



24 



QUESTIONS AND ANSWERS ON 



A. The humidity of the atmosphere. 
94. Q. If we know the height of this column of 
mercury ~vvhat is the next part of the operation? 



r\ 




A. To reduce it to pounds pressure to the square 
inch. 

95. Q. How? 

A. By multiplying it by .49, as this fraction of an 
inch in height of mercury is equal to one pound. 



PUMPS AND PUMPING MACHINERY. 25 

96. Q. Illustrate the process. 

A. If mercury stands at 30 inches, then 30 X.49 = 
14.7 pounds to the square inch. 

97. Q. Having determined the atmospheric 
weight or pressure to the square inch, what is the next 
move ? 

A. To find the height of a column of water that 
this pressure will sustain. 

98. O. How? 

A. By dividing by .434, because this represents the 

height of water that weighs 1 pound to the square 
inch. 

99. Q. Finish the process? 

A. 14.7 -f- .434 = 33.87, therefore it is proper to 
state that the limit of suction power is 34 feet. 

100. Q. Why is it not practicable to set a pump 
34 feet above the surface of water in a well? 

A. For two reasons : First, unless conditions are 
perfect, water can not be raised so high; second, even 
if it were raised it would not flow into the pump with 
sufficient force to give reasonable capacity. 

101. Q. Describe what is meant by perfect con- 
ditions. 

A. The suction pipe must be absolutely tight, and 
every working part of the pump must perform the 
duty for which it was designed. 

102. Q. If for any reason it is desirable to locate 
a pump above an open well, or a river, how would you 
secure the water? 

A. By locating the shaft and gears on a platform, 
then use extended connecting rods and set the pump 
cylinders lower down, as shown in Fig. 13. 

103. Q. What is meant by the lift of a pump? 
A. It means the height that water is raised by suc- 
tion process. 

3 



26 QUESTIONS AND ANSWERS ON 

104. Q. Where water is sent high above a pump, 
what is the process called ? 

A. Forcing water to a given height. 

105. Q. What is the total height or elevation? 




HO. 15 



PUMPS AND PUMPING MACHINERY. 27 

A, It refers to the height attained by both suc- 
tion and discharge operations. 

106. Q. How is it measured? 

A. From the surface of water in the well or river, 
to the highest point to which the pump delivers it. 

107. Q. If the delivery pipe is larger than actu- 
ally necessary, does it put excessive load on the pump, 
due to a greater body of water in the pipe? 

A. The total weight of water is more in a large 
than in a small pipe, but all measurements of pressure 
in such cases are based on the amount per square inch, 
therefore it is the same in both pipes. 

108. Q. What does cause variations in the dis- 
charge pipe of a pump ? 

A. Under proper conditions all changes along this 
line are due to variations in the height to which water 
is elevated. 

109. Q. What would constitute improper condi- 
tions ? 

A. If a valve in this pipe were not wide open it 
would cause increase of pressure on the pump. 

110. Q. Would variations in the speed of pump 
change the discharge pressure? 

A. Yes. If the pipe were only large enough to 
easily deliver the amount discharged under moderate 
speed, the pressure would be raised if the speed were 
increased. 

111. Q. What are the advantages of using a 
motor-driven well pump, fitted with double reduction 
gearing as shown in Fig. 14? 

A. As the motor runs at comparatively high speed 
the first cost is low. This motor starts from a state of 
rest with an easy motion, and its speed may be varied 
to suit conditions. 

112. Q. Is the air chamber shown a necessity for 
such service? 



28 



QUESTIONS AND ANSWERS ON 



A. It is always advisable to use an air chamber 
and in many cases it is absolutely necessary. 

113. Q. Are deep-well pumps usually single act- 
ing? 

A. Yes. 




FIG. M-i 



114. Q. Is it possible for a single-acting pump 
(as the term is generally understood), to deliver a 
nearlv steady stream of water? 

A. Yes. 

115. Q. How is this result secured? 
A. By using a differential plunger. 

116. Q. What does this term mean? 



PUMPS AND PUMPING MACHINERY. 29 

A. It means a plunger made in two separate parts, 
one of which is larger than the other. 

117. Q. Explain the operation of such a plunger. 
A. It is illustrated in Fig. 15 which shows the 

plunger ascending. The check valve 2 is open, allow- 
ing water to pass upward. The larger part of the 
plunger 3 carries the full body of water upward 
above it. 

118. Q. Does it discharge the full quantity of 
water? 

A. It does not. 

119. Q. As the plunger is positive in operation, 
why is only a portion of the water discharged? 

A. Because the upper part 4 is drawn out of the 
water as it ascends, hence some of it must be utilized 
to fill space formerly occupied by the metal. 

120. O. What are the comparative sizes of these 
two parts? 

A. The area of 4 is only one-half of the area of 3. 

121. Q. What is the result of this difference? 
A. Only one-half of the full quantity is discharged 

for each upward stroke. 

122. Q. What becomes of the remainder? 
A. It is discharged on the downward stroke. 

123. Q. Explain this operation. 

A. Fig. 16 shows the plunger descending, there- 
fore the upper part 4 is displacing some of the water 
and forcing it outward through the pipe shown. The 
plunger 3 is simply passing through the water, without 
displacing it. The valve 2 is closed. 

124. Q. Is this a positive operation? 

A. It is. Water will be forced against any pres- 
sure for which the moving parts are designed. 

125. Q. Why is this better than a single-acting 
pump? 

A. Because it delivers water nearly continuously, 
consequently the shocks and jars are less. 



30 



QUESTIONS AND ANSWERS ON 




FI6 15 



PUMPS AND PUMPING MACHINERY. 31 




o 



FIG IS 



32 QUESTIONS AND ANSWERS ON 

126. Q. Does not this really constitute a double- 
acting pump? 

A. Yes ; but it is called a single-acting differential 
pump, to distinguish it from the ordinary double- 
acting machine. 

127. Q. What is the difference between a vertical 
and a horizontal power pump? 

A. The former is fitted with one or more vertical 
cylinders while the latter has horizontal cylinders. 

128. Q. What is a single horizontal power pump? 
A. One that is fitted with only one water cylinder. 

See Fig. 17. 

129. Q. Does this mean that it is a single-acting 
pump? 

A. No. It may be either single or double acting. 

130. Q. What advantage is gained by using this 
type of pump? 

A. There is no advantage, but for personal rea- 
sons it is preferred by many engineers. 

131. Q. Is the friction greater, under given con- 
ditions, than for a vertical pump ? 

A. It may be, but the difference is very small, if 
there is any at all. 

132. Q. Is not the friction of a piston or plunger 
traveling through a horizontal cylinder greater than 
if it were suspended in a vertical cylinder? 

A. If all parts are in perfect alignment the pres- 
sure acting on a horizontal piston will keep it from 
bearing downward. 

133. Q. As force is not always applied in straight 
lines in these pumps, is there not much friction caused 
by this feature alone? 

A. Some friction may be due to this feature, but it 
applies equally to the vertical pump, because force to 
drive it is applied at various angles. 

134. Q. Is there any difference in the lifting 
power of these two kinds of pumps? 



PUMPS AND PUMPING MACHINERY. 




34 QUESTIONS AND ANSWERS ON 

A. No. Either will create a nearly perfect 
vacuum, and that in connection with the density of the 
atmosphere, determines the height to which water can 
be lifted. 

135. Q. What conditions are necessary in order 
to demonstrate this point? 

A. Both pumps must be in good working order. 

136. Q. What is a pot-valve pattern power 
pump? 

A. It is a belt-driven pump with each valve in a 
separate compartment. See Fig. 18. 

137. Q. What are the advantages of this pump? 
A. Each valve can be inspected, cleaned and 

repaired without disturbing anything else. The design 
is naturally strong, hence it is suitable for pumping 
water against heavy pressure. 

138. Q. Is it necessary to run this pump in one 
direction only? 

A. No. It can be run in either direction with good 
results. 

139. Q. Which gives the best appearance? 

A. When the pump runs " over." It means that 
the top of the large gear shown travels from the pump 
valves as indicated by the arrow. 

140. Q. What effect does this have on the cross- 
head during the outward stroke ? 

A. It tends to raise it against the upper guide. 

141. Q. Is it the same on the inward stroke? 
A. Yes. 

142. Q. What is meant by the outward and in- 
ward strokes? 

A. Outward is when the piston rod is coming out 
of the water cylinder. Inward is the opposite stroke. 

143. Q. If the pump runs in the opposite direc- 
tion or " under," what is the effect on the crosshead? 

A. It tends to hold it down on the lower guide. 



PUMPS AND PUMPING MACHINERY. 35 




36 QUESTIONS AND ANSWERS ON 

144. Q. Is this the same as in the case of an 
engine running " over " and " under " ? 

A. No. It is exactly opposite in both cases. 

145. Q. What causes the difference? 

A. The pump is driven by power applied to the 
large gear shown in Fig. 18, which is the same as a 
fly-wheel on an engine, but here power is applied to 
the piston to drive the crosshead and the fly-wheel. 

146. Q. If a third gear is added as shown in Fig. 
19, what effect does it have on the direction of rotation 
when compared with Fig. 18? 

A. If power is taken from another shaft to drive 
the small gear in Fig. 18 the crank shaft of pump will 
revolve in the opposite direction, but when applied to 
the small gear shaft of Fig. 19 the crank shaft will 
revolve the same as the power shaft. 

147. Q. What object is gained by the addition of 
this extra gear? 

A. It enables the pump to deliver a comparatively 
small quantity of water against a much higher pres- 
sure, by using little power. 

148. Q. Does not this show a gain of power due 
to the use of gears? 

A. No. 

149. Q. Why not? 

A. Because the amount of water delivered is com- 
paratively small. The weight of this water is a factor 
in calculating the power developed, hence the final 
result is low. 

150. Q. What object is gained by lowering the 
small gear as shown in Fig. 20? 

A. It requires less floor space, which is a valuable 
consideration in many cases. 

151. Q. Why is the discharge pipe of this pump 
given a long sweep instead of a short turn as provided 
by an ordinary ell ? 



PUMPS AND PUMPING MACHINERY. 37 




38 QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. 39 

A. It prevents jars and friction due to sudden 
change in the direction of flow of water. 

152. Q. Is water elastic? 

A. Strictly speaking, water is a solid body when 
confined in a closed vessel, but in its natural state it 
contains a small proportion of air, and as this is elastic 
it prevents the whole from being classed as solid. It 
can be compressed to a very limited extent. 

153. Q. Does a cubic foot of pure water always 
weigh the same? 

A. No. 

154. Q. What causes variation in weight? 
A. Difference in temperature. 

155. Q. Explain the philosophy of these changes. 
A. If a cubic foot of water at a given temperature 

is heated more or less, the molecules of which it is 
composed are forced farther apart, hence what is 
known as expansion takes place and some of the water 
is forced out, and, of course, the weight is reduced, 
although the cubical contents remain the same. 

156. Q. Is there an exception to this rule? 
A. Yes. 

157. Q. Explain its operation. 

A. If a cubic foot of water at 33° F. is heated to 
the temperature of maximum density, it contracts. 

158. Q. What is the temperature of maximum 
density? 

A. 39° F. If raised above this point it expands. 

159. Q. What is the standard temperature of 
water, for use in ordinary calculations? 

A. 62° F. 

160. Q. Why? 

A. Because it is more convenient to secure than 
the temperature of maximum density. 



40 QUESTIONS AND ANSWERS ON 

161. Q. In the case of a horizontal duplex power 
pump, as illustrated in Fig. 21, what is the advantage 
of setting the pinion shaft and pulley 2 inside the 
crank shaft? 

A. There is no special advantage, except that it 
makes a compact design and thus occupies less floor 
space. 

162. Q. How should the cranks of such a pump 
be set to secure best results? 

A. At right angles. 

163. Q. Explain the matter in detail. 

A. If one side of the pump is on the inside center, 
the other will have made one-quarter revolution from 
the same starting point. 

164. Q. What is meant by the " inside center ?" 
A. When the crosshead is near the cylinder. 

165. Q. If the center of a crank pin is directly 
above the center of the crank shaft, has the crosshead 
made one-half stroke? 

A. Yes; more than one-half. 

166. Q. State the cause of this action. 

A. If it were possible for the crank pin to move 
directly to the crank shaft, then one-quarter of a revo- 
lution would equal one-half stroke; but, inasmuch as 
the crank pin rises, the crosshead must move past the 
middle of its stroke. 

167. Q. What is the advantage of setting the 
cranks at right angles ? 

A. When one water piston is on the center, the 
other is moving at a rapid rate, thus giving a contin- 
uous discharge of water. 

168. Q. How should the cranks of a horizontal 
triplex power pump, as illustrated in Fig. 22, be set? 

A. At angles of 120 degrees. 



PUMPS AND PUMPING MACHINERY. 41 



, I " 1 " I I 








42 QUESTIONS AND ANSWERS ON 



© © o 




o o o 



izzqjil 



O O Q 




© o o 



/ 



M 




n 



o o 



7' 






PUMPS AND PUMPING MACHINERY. 43 

169. Q. How is this point determined? 

A. If we draw a circle to represent the path of the 
crank pins, and place three dots at equal distances 
apart on this circle, each will represent the center of a 
crank pin. 

170. Q. What is the advantage of this design? 

A. As two of the cranks can never be on the cen- 
ter at the same time, water is delivered steadily, thus 
reducing shocks and jars to the lowest point. 

171. Q. How is the length of a stroke of a pump 
determined? 

A. By measuring from the center of crank shaft to 
the center of crank pin. 

172. O. Suppose that a pump is of the " center- 
crank " type, where the above mentioned centers are 
not accessible, how would you determine the stroke? 

A. By watching any point on the crosshead and 
measuring the distance that it travels. 

173. Q. Should the length of crosshead be con- 
sidered? 

A. No ; that has no effect on the distance traveled. 

174. Q. Describe a portable mine pump. 

A. It is a compact, heavy-duty pump, located on a 
truck, so that it can be easily moved from place to 
place on the narrow-gauge tracks over which coal or 
metals are brought out of mines. See Fig. 23. 

175. Q. How are they driven ? 

A. Formerly they were driven by steam or com- 
pressed air. The latter assisted in ventilating the 
mines. Since electric motors have come into general 
use, they are used for this purpose, proving very con- 
venient, as it is only necessary to put up wires to any 
desired point, make proper connections and start the 
pump. 



44 QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. 45 




S 

O 



46 



QUESTIONS AND ANSWERS ON 



176. Q. What is a horizontal vacuum power 
pump? 

A. It is illustrated in Fig. 24. The horizontal 
cylinder is larger in proportion than the preceding 
types, as the pump is designed for light pressures only. 
It is used for removing air from various pipes, tanks, 
etc., used in manufacturing processes. 




F\<o.ZS 



177. Q. Is there a special reason for calling it a 
" vacuum pump " ? 

A. None, except common practice. Every pump 
for general service must create a vacuum in the suction 
pipe, in order to raise water or other liquids, hence 



PUMPS AND PUMPING MACHINERY. 47 

the term " vacuum " applies to all, except a very small 
class that are designed for forcing only. 

178. Q. What is the disadvantage of a power 
vacuum pump? 

A. It can only be operated when the shafting of a 
mill or shop is running, and the speed can not be 
changed at pleasure. 




179. Q. What are the advantages of a double 
vacuum pump, as illustrated in Fig. 25 ? 

A. It gives large capacity for comparatively small 
floor space, and a steady vacuum is maintained on 
account of the continuous effect of the pumps. 

180. Q. What is a force pump? 

A. Any pump that forces water against pressure 
might properly be called a force pump; but, by one 
of those freaks of practice which are found occa- 
sionally, a pump that is nearly always used to send 
water against a light pressure is known as a force 
pump. See Fig. 26. 



48 QUESTIONS AXD ANSWERS ON 

181. Q. Then why is it called a force pump? 

A. To distinguish it from the kind that can only 
raise water and let it flow away on the surface. 

182. Q. How can this pump be arranged to dis- 
charge water upward? 

A. By removing the cap on the vertical outlet and 
screwing it on the discharge connection at the left 
hand. 

183. Q. Fig. 26 is an end view and Fig. 27 a side 
view, or elevation, of the same kind of pump. In 
what respect are they different? 

A. The former is fitted with a driving shaft, carry- 
ing a tight and a loose pulley. This does not require a 
balance-wheel. The latter is driven by an electric 
motor. The pinion on this motor shaft meshes into 
a large gear on the pump shaft, which acts as a bal- 
ance-wheel. 

184. Q. Which is the most efficient? 

A. For a pump located near the source of power, 
the belt drive is more efficient; but if power must be 
transmitted a long distance, the motor will show best 
results. 

185. Q. To what general type of pump do these 
belong? 

A. They are rotary pumps. 

186. Q. Describe a rotary pump. 

A. The simplest form of this type of pump is illus- 
trated in Fig. 28. It consists of two gears suitably 
mounted on short shafts that are carried by an ellip- 
tical casing. Power is applied to one, and the other 
is turned the same as any other form of gears. 

187. Q. How does this action cause water to 
flow? 

A. The gears run close to the casing, but do not 
touch it. As water is trapped between the stationary 
and the revolving part, it is forced around through a 



PUMPS AND PUMPING MACHINERY. 49 




50 



QUESTIONS AND ANSWERS OX 



little more than one-half of the circle, where it meets a 
like quantity discharged from the opposite side. As 
the discharge opening is located at this point, the water 
is forced out through it. 




FlCb.2.8 



PUMPS AND PUMPING MACHINERY. 51 

188. Q. Will such a pump operate on a high lift? 
A. It will, provided the pump and suction pipe are 

primed or filled with water from some other source 
before the pump is started. However, all such pumps 
should receive their supply under a low head, or the 
lowest possible lift, if the full capacity is desired. 

189. Q. Is this type of pump suitable for raising 
water containing sand or other foreign matter? 

A. It is better adapted to such service than any 
other form of power-driven pump, although it is, of 
course, desirable to have the water as clear as possible, 
unless the object is to move earth from one point to 
another. 

190. Q. Is this pump adapted to fire service? 

A. Yes; it is especially fitted for such work on 
account of the perfectly steady stream delivered, as 
there is no reverse action in its operation. 

191. Q. Is it safe to start this pump quickly in 
case of emergency? 

A. Yes ; there are no reciprocating parts to cause 
shocks and jars when the motion of water is reversed, 
hence the ability to start quickly in case of fire is one 
of the valuable features of this machine. 

192. Q. To what machine in common service 
may a rotary pump be compared? 

A. To a pressure blower, supplying air for a 
foundry cupola. 

193. Q. Is it similar to a rotary engine? 

A. Yes; but a rotary engine is driven by steam 
passing through it, while a rotary pump forces water 
through its internal mechanism. 

194. Q. Are these pumps limited to rough and 
coarse service, such as contractors' work, quarry opera- 
tions, etc. ? 

A. No; some of them are used in high-grade fire 
engines, where they are found to be reliable and effi- 
cient. 



52 



QUESTIONS AND ANSWERS ON 



195. Q. Give an illustration of this record. 
A. Fig. 29 shows a form of rotary pump that is 
used in the Silsby fire engine. 




196. Q. What modifications are made in this im- 
proved pump? 

A. More teeth are used in the cogs, and they are 
not all alike. Packing strips are provided for the longer 
ones. 



PUMPS AND PUMPING MACHINERY. 53 



197. Q. Describe another kind of rotary pump. 
A. Fig. 30 shows Gould's improved pump, in 

which cams are used instead of cogs. 

198. Q. What is the object of this improvement? 
A. To reduce friction and wear, and at the same 

time make the pump more efficient. 

199. Q. Will this pump raise water without 
priming? 

A. Yes; it will do this equal to any other kind, 
and much better than some of them. 

200. Q. How are these results secured? 

A. The casing is bored true and smooth and the 
cams are accurately fitted to it, thus securing a nearly 
perfect fit between the stationary and the revolving 
parts. 




FiG3o 



54 QUESTIONS AND ANSWERS ON 

201. Q. Previous illustrations show rotary pumps 
in which one internal part drives the other by contact 
of gears. Do all rotary pumps operate on this prin- 
ciple? 

A. No. 

202. Q. What other principle is adopted, and how- 
does it operate in practice? 

A. The internal parts are mounted on two shafts 
that extend outward through the casing. External 
gears of equal diameter and pitch drive the shafts and 
maintain the internal parts in proper relative position. 

203. Q. Illustrate one of these pumps. 

A. Fig. 31 shows one kind of Roots pump with 
two impellers, which revolve as indicated by arrows. 

204. Q. Do these impellers come in contact with 
each other? 

A. They do not, but there is only a narrow space 
between them. 

205. Q. If either shaft is given one-quarter revo- 
lution, what is the effect? 

A. The other turns the same distance. The right- 
hand impeller then stands vertical, while the left-hand 
takes a horizontal position. 

206. Q. Describe another kind of rotary pump. 
A. Fig. 32 shows a pump similar to the preceding, 

but it is fitted with three impellers. 

207. Q. Are these parts sometimes called by 
other names? 

A. Yes; they are known as lobes, or wings. 

208. Q. Describe the action of these pumps. 

A. The space in front of each lobe, or wing, is 
filled with water, which is pushed along in advance 
of it until the discharge opening is reached, when it is 
forced out into the discharge pipe. 

209. Q. Why does the water not churn around 
with the wings instead of being forced outward? 



PUMPS AND PUMPING MACHINERY. 55 




FIG/51 



56 



QUESTIONS AND ANSWERS ON 



A. Because the water that is sent in advance of 
one comes in contact with that sent along by another 
which is going in the opposite direction. As the two 
bodies meet they must go somewhere, hence they turn 




FIG. 32. 



upward and go out into the discharge pipe, as above 
mentioned. 

210. Q. On which shaft must the pulley that 
receives the belt be placed? 

A. It makes no special difference, as either will 
give good results. 



PUMPS AND PUMPING MACHINERY. 57 

211. Q. Is there an advantage gained by the use 
of three lobes instead of two? 

A. The discharge of water is more uniform for the 
same speed of shafts, and the slip is less. 

212. Q. What does the term " slip " mean, as 
used in this connection? 

A. It is the difference between the space between 
the lobes multiplied by the number of revolutions in 
a given time, and the quantity of water delivered in 
the same time. 

213. Q. Why are these usually not the same? 

A. Because more or less water slips back between 
the lobe and the casing. 

214. Q. What slip should be allowed when cal- 
culating the capacity of such pumps? 

A. From five to fifteen per cent. 

215. Q. Why is it not the same in all cases? 

A. Because it increases as the discharge pressure 
is raised. 

216. Q. What will increase the discharge pres- 
sure above what good practice allows? 

A. Pumping water through pipes which are too 
small, using short ells, too many valves, and valves of 
unsuitable design. 

217. Q. What condition renders a high discharge 
pressure unavoidable? 

A. Elevating water to a great height. 

218. Q. Is it possible to find conditions under 
which there would be no slip ? 

A. Yes. 

219. Q. Describe these conditions. 

A. If the lift is low, the pump speed high, and 
water is elevated but a few feet above the pump, there 
may be no slip. 

220. Q. Explain the philosophy of this action. 

A. When a body of water is set in motion through 



58 



QUESTIONS AND ANSWERS ON 



a long pipe, the momentum created causes it to over- 
come the effects of irregular motion in the pump, and 
it rushes forward in a nearly continuous stream. 




FIG.33 



221. Q. Describe another kind of rotary pump. 

A. Fig. 33 illustrates a rotary pump invented by 
J. Eve. It consists of a hollow cylinder, 2, revolving 
in a case, 3, indicated by the arrow. The drum has 
three projections, as shown, that are close fits in the 
case, therefore but little water can pass or leak at this 
point. 



PUMPS AND PUMPING MACHINERY. 59 

222. Q. What prevents water from going down 
the suction pipe 4? 

A. The small cylinder, 5, fills this space for a 
greater part of each revolution of 2, but a portion of 
it is cut away to allow the projections to pass. The 
cylinders 2 and 5 are maintained in proper relative 
position by gears of suitable dimensions. As water 
can not pass 5, it is forced out through the discharge 
pipe 6. 

223. Q. What other principle is adopted in the 
design of rotary pumps ? 

A. An eccentric revolving in a cylinder, as shown 
in Fig. 34. 

224. Q. Describe the operation. 

A. The eccentric, 2, revolving on its shaft moves 
very close to the casing, thus sending water in advance 
of it. The sliding partition, 3, prevents it from passing 
this point, hence it goes out of the discharge pipe, as 
shown by the arrow. A check valve prevents water in 
advance of the eccentric from going back into the suc- 
tion pipe. 

225. Q. Is there another principle utilized in the 
operation of rotary pumps? 

A. Yes; a round cylinder is caused to revolve in 
an irregular casing, as shown in Fig. 35. A sliding par- 
tition, 2, is forced outward by spiral springs, thus 
making a water-tight joint at the casing. On account 
of the irregular shape of the casing, water can not pass 
the discharge pipe, hence it is delivered for useful 
purposes. 

226. Q. What principle is employed in delivering 
water with centrifugal pumps? 

A. Centrifugal force, as indicated by the name. 

227. Q. What does this name mean? 
A. Thrown out from a center. 



60 



QUESTIONS AND ANSWERS ON 



228. Q. How is this name divided into syllables 
and accented? 

A. As follows, with accent on the second syllable : 
11 cen-trif-u-gal." 

229. Q. Illustrate the application of this force. 




F1&.34- 



PUMPS AND PUMPING MACHINERY. 61 

A. It may be compared to a curved pipe, pivoted 
at the center and fed with water at the same point. 
This pipe is turned rapidly like a pin-wheel, as illus- 




RO.35 



trated in Fig. 36. This water is forced into a casing 
which gradually widens, as shown at 2, until it 
broadens into the discharge passage, 3. 

230. Q. How is water taken by this pump? 



62 QUESTIONS AND ANSWERS ON 

A. It is drawn into the central opening, 4. 

231. Q. What course does it follow after enter- 
ing the pump? 

A. This course is further illustrated in Fig. 37, 
which is an end view of the pump. It divides and is 
carried in a circle. 




FiO. t>(o 



232. Q. As water flows in very rapidly, does it 
not cause severe end thrust on the driving-shaft? 
A. Yes, but it has no chance to heat. 



PUMPS AND PUMPING MACHINERY. 63 

233. Q. What name is given this kind of centrifu- 
gal pump? 

A. It is known as the single-suction pump. 




nG,37 



234. Q. Does this design cause unnecessary fric- 
tion? 

A. Yes, but no special trouble is caused by it, 
except that it requires more power. 

235. Q. How is this undesirable feature dis- 
posed of? 

A. By use of the double-suction pump, shown in 
Fig. 38. 



64 QUESTIONS AND ANSWERS ON 




FIG. 38 



PUMPS AND PUMPING MACHINERY. 65 

236. Q. Explain the principle on which it oper- 
ates. 

A. Water enters from both sides, hence the thrust 
on one is balanced by the other, resulting in very- 
slight friction. 

237. Q. Is Fig. 39 a horizontal or a vertical 
pump? 

A. Properly speaking, this is a vertical pump, 
because the pump stands vertically, and it is so desig- 
nated by theoretical experts, but according to common 
practice among steam engineers it is a horizontal 
pump. 

238. Q. Why is it so called? 

A. Because the position of the shaft fixes the 
name, rather than that of the pump. 

239. Q. What is the device shown at the left 
hand? 

A. It is a primer, by means of which water to 
start the pump is supplied. 

240. Q. Is Fig. 40 a horizontal or a vertical 
pump? 

A. According to English practice, it is a hori- 
zontal pump, but in our service it is known as a verti- 
cal pump, because the shaft stands upright. 

241. Q. What is a double-acting centrifugal 
pump? 

A. One that can be run in either direction with 
equally good results. 

242. Q. Why is this kind desirable? 

A. When setting it up it is not necessary to locate 
it to run in a given direction, which may be inconve- 
nient on account of local conditions. These may be 
disregarded and the pump set where it will be most 
convenient to operate. 

243. Q. What is a right-hand centrifugal pump? 



66 QUESTIONS AND ANSWERS ON 







UJ LU LL) LU ">ll B CT 







PUMPS AND PUMPING MACHINERY. 07 

A. When standing at the suction side, the dis- 
charge is at the right hand, and the pump revolves 
from right to left, or opposite to the hands of a watch. 




Fio -4-0 



244. Q. What is a left-hand pump? 
A. The discharge is at the left hand; the motion 
agrees with the hands of a watch. 



68 QUESTIONS AND ANSWERS ON 

245. Q. If a centrifugal pump delivers full capac- 
ity when started, but the discharge grows less, what 
is the probable cause? 

A. The supply of water may be less than the 
capacity of pump, the level may be lowered until the 
lift is too high for the speed, or air may leak into the 
suction connections. 

246. Q. Why should the pipes all be of full size? 
A. To admit of delivering full capacity with least 

power. 

247. Q. Will short turns in the suction pipe 
reduce the amount of water delivered? 

A. Yes ; because they increase friction. 

248. Q. If a valve in the delivery pipe is closed, 
will it cause the pump to burst from over-pressure? 

A. No; the water will simply churn around in the 
pump. 

249. Q. Why is this true? 

A. Because the centrifugal pump is not a positive 
acting machine like a power pump. 

250. Q. What causes water to flow continuously 
under nQrmal conditions? 

A. The body of water is started into action with- 
out special opposition, after which the momentum is 
maintained so long as the pump turns and the dis- 
charge valve is open. 

251. Q. Into what classes may improved modern 
centrifugal pumps be divided, for convenient reference ? 

A. Three general classes: conoidal, volute and 
turbine. 

252. Q. What does the word " conoidal" mean? 
A. It means that the article to which it is applied 

resembles a cone. In this special connection it conveys 
the idea that water is thrown into the form of a cone, 
during the process of pumping from a lower to a higher 
level. 



PUMPS AND PUMPING MACHINERY. 69 

253. Q. What is a motor-driven, single conoidal 
pump? 

A. It means one of these important pumps driven 
by direct connection to an electric motor. See Fig. 41. 




Fie.**/ 



254. Q. What is a motor-driven twin conoidal 
pump? 

A. It means two of these pumps mounted on one 
shaft and driven by an electric motor located between 
them as illustrated in Fig. 42. 

255. Q. To what height will the ordinary centrif- 
ugal pump force water on an economical basis? 

A. About fifteen feet or less. 

256. Q. Can it be made to force water higher? 
A. Yes, but at reduced efficiency. 

257. Q. Explain the meaning of this term. 

A. It means that in order to force water much 
higher the speed must be excessive, thereby causing 
great loss by friction. 

258. Q. To what height will the conoidal class 
force water, with reasonable efficiency? 

A. About thirty feet. 

259. Q. What are the advantages of the twin 
type over the single motor-driven pump ? 



70 QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. 71 

A. Large capacity is secured without using ex- 
cessively heavy and cumbersome single machines. If 
one is accidentally broken in service, only one-half of 
the pumping plant is disabled. The whole machine is 
well balanced by the location of a pump on each side of 
the motor. The floor space required is comparatively 
small. 

260. Q. Is it necessary to use both pumps in the 
same service? 

A. No. Each one may be used on entirely sep- 
arate service. 

261. Q. What does the term " volute " mean? 

A. Relating to a spiral. In this connection it re- 
fers to the motion given to water as it is elevated. 

262. Q. What is the special advantage of the 
volute pump? 

A. Its great efficiency when operating against me- 
dium heads. 

263. Q. State the efficiency secured in service and 
explain it. 

A. Eighty-five per cent has been realized. It 
means that for each horse-power applied to the pump 
.85 appears in the form of water actually elevated. 

264. Q. What is meant by " medium heads " in 
this connection? 

A. It means about twice the heads for which 
conoidal pumps are recommended. 

265. Q. Describe the appearance of these pumps. 
A. They do not differ radically from other centrif- 
ugal pumps in this respect. 

266. Q. What does the term " turbine " mean 
when used in this connection ? 

A. It means an improved form of pump which is 
efficient when operating against very high heads. 

267. Q. Why is this term adopted? 



72 QUESTIONS AND ANSWERS ON 

A. Because the turbine water wheel has been 
greatly improved since its first appearance. The tur- 
bine pump resembles it when compared to the early- 
forms of centrifugal pump. 

268. Q. What is a two-stage turbine pump? 

A. It is practically two pumps closely connected. 

269. Q. What special advantage does this form 
possess, not found in the single-stage pump? 

A. It will operate against high heads at com- 
paratively low speed, therefore it may be driven by 
direct connection to a steam engine as shown in Fig. 
43. 

270. Q. What is considered " comparatively low 
speed " in such a case? 

A. Three hundred revolutions per minute. 

271. Q. Explain the principle adopted in a two- 
stage turbine pump? 

A. One pump raises water from a lower level and 
delivers it to the second, which elevates it as required. 

272. Q. What other name is given to this kind? 
A. It is called a compound pump. 

273. Q. Why is it so called? 

A. Because it resembles a compound steam engine. 

274. Q. How does it resemble such an engine? 
A. The engine uses the same steam twice. The 

pump operates on the same water twice. 

275. Q. What is a triple turbine pump? 

A. It consists of three pumps mounted on one 
shaft. Water passes through each in succession. 

276. Q. Describe a quadruple turbine pump. 

A. It is four pumps mounted on one shaft, as illus- 
trated in Fig. 44. Water is given increased velocity by 
each in turn. 

277. Q. What is the principal improvement made 
in these pumps, so far as outward appearance is con- 
cerned? 



PUMPS AND PUMPING MACHINERY. 73 




74 QUESTIONS AND ANSWERS ON 




1 


i 

J 


h .1.1 




i<:» 


■ in 


«*« 





PUMPS AND PUMPING MACHINERY. 75 

A. The separate pumps were brought closer to- 
gether, as illustrated in Fig. 45, making a very compact 
machine that occupies but little space. 

278. Q. Explain the advantage of this improve- 
ment in relation to internal operation, or action. 

A. It reduces the friction of water when passing 
from one stage to another, owing to short and direct 
passages as illustrated in Fig. 46. 

279. Q. What other advantage is gained? 

A. It lowers the capital required to install a plant 
by reducing the cost of production. 

280. 0. Can the turbine principle be applied to 
vertical centrifugal pumps? 

A. Yes. This is shown in Fig. 47, which is a large 
vertical single-stage turbine, supplying water-works in 
regular service. 

281. 0. Is it practicable to design and use a two- 
stage, vertical, turbine centrifugal pump? 

A. Yes. This principle operates well in practice. 
A pump of this type is shown in Fig. 48. 

282. Q. Can a triple, vertical pump be designed 
that will prove reliable and efficient? 

A. Yes, also a four-stage or quadruple pump, one 
of which is shown in Fig. 49. 

283. Q. Is the suction inlet located at the bottom 
of this pump? 

A. No. Water enters at the top and is discharged 
at the bottom as illustrated in Fig. 50. 

284. Q. How are the heavy internal revolving 
parts of such a pump supported? 

A. When the pump is not in service they rest on 
a bearing near the top of the driving shaft. 

285. 0. As water goes downward into the pump 
does not this action add greatly to the weight on the 
supporting bearing? 



76 QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. 77 




<0 

t 
a 



78 



QUESTIONS AND ANSWERS ON 



A. No. By the use of a very ingenious device, 
water passing to the lower part 2 acts as a cushion, and 
automatically relieves this bearing of all weight due to 
the internal mechanism, also of the vertical shaft. 




FIO.^7* 



286. Q. How would you proceed to start a 
centrifugal pump, with a lift of ten feet or more, with- 
out a foot valve in the suction pipe? 

A. Shut the discharge valve, then use the device 
provided to draw air out of the suction pipe. When 



PUMPS AND PUMPING MACHINERY. 79 



water fills the pump, start it into operation, then open 
the discharge valve. 

287. Q. Why should the discharge valve be 
closed? 

A. To prevent air from coming back through the 
discharge pipe. 

an 




288. Q. What is provided for drawing air out of 
the suction pipe? 

A. A hand pump, or a steam ejector. 

289. Q. Why is it not practicable to draw this air 
out with the main pump ? 

A. Because the revolving parts of a centrifugal 
pump are not an airtight fit in the casing. 



80 QUESTIONS AND ANSWERS ON 




F«G.-f9 



PUMPS AND PUMPING MACHINERY. 81 




Fl& SO 



82 QUESTIONS AND ANSWERS ON 

290. Q. With the same lift, provided there is a 
foot valve in the suction pipe, how would you proceed ? 

A. Shut the discharge valve, let water run into the 
suction pipe from some external source until the pump 
is full, start the pump and open the discharge valve. 

291. Q. Why should the discharge valve be 
closed until after the pump is started? 

A. To secure a solid body of water in the pump. 

292. Q. Suppose that there is not a supply of 
water above the pump from which it can be filled, how 
would you proceed? 

A. A steam pump, an ejector, or a hand pump 
should be provided for this purpose. If neither of these 
are available, water must be secured from the nearest 
stream or well to start the pump. 

293. Q. If the main supply of water is on a level 
with the pump, or above it, how would you start the 
pump? 

A. Open the stop valve in the suction pipe, also 
the discharge valve and start the pump. 

294. Q. Is it necessary to have a valve in the suc- 
tion pipe under such conditions? 

A. While it is possible to operate a centrifugal 
pump without such a valve, to omit it would be proof 
of bad engineering. 

295. Q. Why is it necessary, or at least very de- 
sirable? 

A. To enable the engineer to shut off the supply 
whenever it is necessary to inspect the internal parts. 
In cold weather this water might freeze and cause 
trouble if it could not be shut off. 

296. Q. Why would you open the discharge 
valve before starting the pump under this condition? 

A. To secure a solid body of w r ater in all pipes and 
passages. While this may not be necessary in all cases, 
it can do no harm. 



PUMPS AND PUMPING MACHINERY. 83 

297. Q. Is a strainer required on the end of the 
suction pipe in all cases? 

A. If the end of suction pipe is but little below the 
surface of a river, a strainer will be of greater value 
than if water is taken several yards below the surface, 
but it should never be omitted. 

298. Q. What kind is recommended? 

A. Where continuous service is wanted, a duplex 
strainer is necessary in order that one part may be 
cleaned while the other is in service. 

299. Q. What is the disadvantage of a long 
strainer, of about the same diameter as the suction 
pipe, when placed in a vertical position? 

A. If the water level varies much, the upper part 
of the strainer may be exposed, allowing air to flow to 
the pump. 

300. Q. If a short strainer is used, why should it 
be much larger than the suction pipe? 

A. Because the actual area of openings should be 
about double the area of the pipe, to provide for partial 
closing of it by foreign matter. 

301. Q. Describe the main features of a crank and 
fly-wheel boiler-feed pump. 

A. It consists of a steam cylinder containing a 
piston, the rod of which extends into the water cylin- 
der. A piston in this cylinder acts directly on the 
water, and forces it out through suitable valves. 

302. Q. How is steam admitted to and exhausted 
from this cylinder? 

A. Usually by a plain " D " slide valve. 

303. Q. Is the supply of steam cut off early in 
the stroke, to allow for expansion? 

A. No; it is admitted during about seven-eighths 
of the stroke. 



84 QUESTIONS AND ANSWERS ON 

304. Q. How is the motion reversed in this kind 
of pump? 

A. By means of a crank shaft, and the momentum 
of a cast-iron fly-wheel. See Fig. 51. 

305. Q. How are connections made in this case? 
A. The crank shaft, carrying the fly-wheel, is next 

to the water cylinder. The crosshead is wide enough 
to carry one end of a connecting rod on each side of 
the water cylinder. The other ends of these rods are 
rigidly connected to a supplementary crosshead, the 
center of which is fitted with crank-pin boxes, gib, 
strap and key, according to common practice in steam- 
engine design and construction. 

306. Q. Does this form a center or side crank? 
A. It is a center crank, because a bearing is pro- 
vided on both sides of it. 

307. Q. How many fly-wheels are used? 

A. In this particular case only one is used, but two 
could be provided with good results. 

308. Q. What advantage would be gained by 
adding, another wheel? 

A. It would give a more uniform motion to the 
machine and allow it to be run at a lower speed. 

309. Q. Why is a low speed a valuable feature? 
A. Because the supply of water to a boiler can 

thus be reduced when the rate of evaporation is low. 

310. O. Why not stop the pump and let it stand 
until more is needed? 

A. Because the water level should not be allowed 
to vary much, but ought to be kept as nearly uniform 
as possible. 

311. Q. Is the crank shaft always located near 
the water cylinder? 



PUMPS AND PUMPING MACHINERY. 85 




86 QUESTIONS AND ANSWERS ON 

A. No; it is sometimes placed near the steam 
cylinder, as shown in Fig. 52. 

312. Q. What advantage is gained by this design? 
A. There is none. It is a matter of choice or con- 
venience of the builders. 

313. Q. In what other way does this differ from 
the preceding illustration? 

A. The crank is outside of the fly-wheel. The 
same arrangement is found on the other side, as there 
are two fly-wheels. 

314. Q. Why are these called 'fly-wheels? 

A. The term is used here in order to agree with 
common practice, and not because it is considered 
strictly correct. 

315. Q. What is a better name for them? 

A. Balance wheels, as they tend to balance the 
pumps and give more satisfactory motion in service. 

316. Q. Describe this motion. 

A. Assuming a uniform motion of the wheel, the 
crosshead moves slowly during the early part of each 
stroke, increases rapidly as the middle is approached, 
and is reduced during the latter part. 

317. Q. Does it stop at the end of every stroke? 
A. Yes; at low speed the stop is plainly seen. 

318. Q. How does this operate, so far as the 
water piston and valves are concerned? 

A. The piston is given motion that does not result 
in severe shocks and jars. The valves are opened and 
closed slowly. 

319. Q. What other plan is adopted for the loca- 
tion of these wheels ? 

A. They are sometimes located between the cylin- 
ders, or at least the shaft is there, as shown in Fig. 53. 

320. Q. What advantage is gained by this design? 
A. No special advantage is secured by it. 



PUMPS AND PUMPING MACHINERY. 87 




88 



QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. 89 

321. Q. What device is here used to convert the 
reciprocating motion of the piston rod into the rotary 
motion of the crank shaft? 

A. A Scotch yoke. 

322. Q. How does the motion of this yoke differ 
from that secured by a crank and connecting rod? 

A. Starting from the inside center, when the wheel 
has made one-quarter revolution, the piston has moved 
through one-half stroke. For the same movement of 
the wheel, the crank and connecting rod cause the 
piston to move more than one-half stroke, making the 
latter part short accordingly. With the Scotch yoke, 
one-quarter revolution of the wheel gives one-quarter 
of a double stroke at all times. 

323. Q. The preceding horizontal pumps shown 
are used for pumping water under more or less pres- 
sure. Are similar pumps used for another purpose? 

A. Yes; Fig. 54 shows a crank and fly-wheel 
duplex pump that is designed for pumping air to use 
in racking off beer, etc., also for use in elevating water, 
by what is known as the air lift. 

324. Q. What advantage is gained at the steam 
end by use of a duplex pump? 

A. Steam can be cut off earlier in the stroke, thus 
securing the economy due to more expansion. 

325. Q. What advantage is gained on the air end? 
A. It is practicable to run the pump very slowly 

when only a small volume of air is wanted, and pump 
only what is required without stopping on the center. 

326. Q. Is it possible to design the steam and air 
cylinders so that when the required pressure is secured 
in the air tank there will not be enough force acting on 
the air piston to create a higher pressure? 

A. Yes ; it is possible, but not practicable. 

327. Q. Why? 

A. Because such a machine would only be fit for 
use under a given steam pressure, and a corresponding 



90 QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. 91 

air pressure. Any variation from these standards 
would cause the pump to stop, or else run at an excess- 
ive speed. 

328. Q. What device is used on these pumps to 
secure steady air pressure? 

A. A pump governor, or speed regulator. 

329. Q. How does this operate in practice? 

A. When the required air pressure is secured, the 
steam pressure is greatly reduced, or entirely shut off. 
A slight reduction in the air pressure causes the steam 
to be turned on again. 

330. Q. For what other purpose is a horizontal 
air pump used? 

A. For creating a partial vacuum in pans used in 
the process of making sugar, and in similar industries. 
Fig. 55 shows one of these machines. 

331. Q. What is the governor for in this case? 

A. To prevent excessive speed in case that too 
much steam is turned on at the throttle valve. 

332. Q. For what special system is this pump 
designed? 

A. For the wet system, because water is used in 
the pumping process. 

333. Q. What other system is used in such proc- 
esses? 

A. The dry system, because air is pumped dry. 

334. Q. Why is a vacuum required in such cases? 
A. Because it lowers the temperature necessary 

for boiling the crude materials, therefore it is not dam- 
aged by heat. 

335. Q. What are the advantages of the vertical 
crank and fly-wheel pump, or the Scotch yoke and fly- 
wheel type, as illustrated in Fig. 56? 

A. It occupies a very small amount of floor space 
for the capacity of pumps. As both steam and water 
pistons are suspended in the cylinders there is but little 
friction to overcome. 



92 QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. 93 

336. Q. What are its disadvantages? 
A. There are no special disadvantages, except that 
it is difficult to maintain steady speed when only a 




FiO.56 

small quantity of water is to be forced against a high 
pressure. 

337. Q. What causes the varying speed? 



94 QUESTIONS AND ANSWERS OX 

A. On the downward stroke the weight of steam 
and water pistons, rods, crossheads, etc., assist the 
steam pressure, but on the upward stroke this weight 
acts against the steam pressure. 

338. Q. How can this inequality be counterbal- 
anced? 

A. By extra weight on one side of the fly-wheel. 

339. Q. Are pumps of this type ever designed for 
double service? 

A. Yes ; Fig. 57 illustrates one of these pumps. 

340. Q. Describe its design and operation. 

A. There are two water pistons on one rod, and 
both are single-acting. The upper piston forces water 
into the boiler on the downward stroke. Water is 
raised from a well or river into an elevated tank by the 
lower piston on the upward stroke. 

341. Q. Mention another service in which verti- 
cal pumps are used to good advantage. 

A. Fig. 58 illustrates a duplex vertical air pump, 
used in connection with condensing engines. 

342. Q. Why is it called an air pump? 

A. Because it pumps steam, water and air out of 
the steam-engine cylinder. 

343. Q. What advantage is thus gained? 
A. Nearly all back pressure is removed. 

344. Q. Describe another pumping system in 
w r hich vertical pumps are used with good results. 

A. In transferring oils and gases from one point 
to another. Fig. 59 shows one of these pumps. 

345. Q. Is this a single or double acting pump? 
A. As it is fitted with four valve boxes, it must be 

of the double-acting type. All valves are thus rendered 
accessible. 

346. Q. Is it necessary to run such pumps at a 
low speed? 

A. This is not generally wanted, because the 



PUMPS AND PUMPING MACHINERY. 95 

required quantity of oil may be pumped and the pump 
is then shut down. When transferring gas steady 
service is required, therefore the proper size of pump 
must be supplied to give the minimum quantity at 

reliable speed. . . 

347. Q. Name other systems in which vertical 

pumps are used. 




FIG. 57 



96 QUESTIONS AND ANSWERS ON 




FIG-.58 



PUMPS AND PUMPING MACHINERY. 97 

A. In acid-works, for the removal of obnoxious 
and dangerous fumes, also in the bisulphite process of 
papermaking. Fig. 60 illustrates a vertical, duplex air 
pump, or exhauster. 




Fi<b.59 



348. Q. Why are the air cylinders larger than the 
steam cylinders? 

A. Because steam at high pressure is used, while 



98 



QUESTIONS AND ANSWERS ON 



air, or other gases and fumes, are transferred at low 
pressure and large volume. They are fitted with 
mechanically operated valves. 




Fio.60 



349. Q. How do these valves differ from ordinary 
pump valves? 

A. They are opened and closed by eccentrics on 



PUMPS AND PUMPING MACHINERY. 09 

the crank shaft, therefore the movements are independ- 
ent of the gases passing through them. They would 
operate in the same way if no work was done by the 
pump. 

350. Q. For what additional purpose can this 
machine be used? 

A. It can be utilized as a steam engine for driving 
machinery. By providing steam cylinders larger than 
the pumps require, power for running a belt on the fly- 
wheel can be secured, and this may be transmitted to 
shafting according to common practice. 

351. Q. Name the most popular boiler feeder in 
use at the present time. 

A. The direct-acting steam pump, when used in 
connection with an exhaust-steam feed-water heater. 

352. Q. Into what two classes are direct-acting 
steam pumps divided by common practice? 

A. Single and duplex. 

353. Q. Give a brief description of a single pump. 
A. A steam cylinder and a water cylinder are set 

tandem. The steam piston and the water piston are 
connected by a rod. Steam acts on the former and 
thus drives the latter. 

354. Q. Describe a duplex pump. 

A. It consists of two single pumps set side by side. 

355. Q. Which was invented first? 
A. The single pump. 

356. Q. Who invented it, and when? 

A. Henry R. Worthington. It was patented in 
1841. 

357. Q. For what purpose was it used? 

A. It was used to feed a steam boiler. A float 
was located inside of this boiler, and it was connected 
by levers and springs to the throttle valve of the 
pump; hence, when the water level fell below a cer- 
tain point the throttle valve opened and the pump was 
supposed to start. 



100 QUESTIONS AND ANSWERS ON 

358. Q. Did it always respond to this action? 
A. No ; it was not reliable in service. 

359. Q. Describe this pump. 

A. It is illustrated in Fig. 61. The side rod car- 
ries a tappet that engages a swinging lever, and opens 
and closes the steam valve. 

360. Q. How was the amount of water delivered 
regulated? 

A. By varying the speed, also by changing the 
length of stroke. 

361. Q. Describe another kind of direct-acting 
steam pump of early design. 

A. It is shown in Fig. 62. It is of the plunger 
type, and steam is admitted by what the inventor 
called a B valve, as it is fitted with two exhaust 
cavities. 

362. Q. How was this valve operated? 

A. As the water plunger neared the end of either 
stroke, the water pressure was suddenly reduced, con- 
sequently the steam piston and rod, carrying the tap- 
pet shown, jumped quickly to the end of the stroke. 
This action struck the valve rod a blow which moved 
the steam valve, admitted steam to the opposite end 
of the cylinder, and reversed the steam piston. 

363. Q. Was this pump an unqualified success? 
A. No; the irregular speed of the piston was not 

satisfactory, especially when working to full capacity. 

364. Q. Is the direct-acting steam pump an eco- 
nomical machine, so far as steam consumption is con- 
cerned? 

A. No; it was not when first put on the market, 
and has never been made so, up to the present time. 

365. Q. Then why are they so extensively used? 
A. Because they are more convenient than any 

other form of boiler feeder. 

366. Q. If steam at, say, 100 pounds pressure by 
the gauge, is admitted to the steam cylinder of a pump, 



PUMPS AND PUMPING MACHINERY. 101 







102 QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. 103 

where it acts on the piston, and the water piston must 
act against the same pressure, why does not the piston 
stand still? 

A. Because the steam piston of a boiler feeder is 
larger than the water piston. 

367. Q. Explain the principle of operation. 

A. Fig. 63 shows the two pistons connected by a 
rod. This illustrates a 14 by 7 by 12 inch pump. The 
area of a 14-inch circle is 153.9 square inches, while 




the area of a 7-inch circle is 38.38 square inches. As 
one is four times the area of the other, the larger one 
will easily force the smaller against the same, or even 
a higher pressure. 

368. Q. When stating the dimensions of a pump, 
does the order in which the figures are given have any 
particular meaning? 




no. 64; 



A. Yes; the diameter of steam cylinder is stated 
first, then of the water cylinder or plunger, and last 
the stroke. 

369. Q. Some pumps are fitted with steam and 
water pistons of the same diameter. See Fig. 64, 



104 QUESTIONS AND ANSWERS ON 

which is 10 by 10 by 12 inches. Could such a pump 
be used to feed a boiler? 

A. No, not if steam to operate it is taken from the 
same boiler, as the piston would not move. If steam 
were taken from another boiler carrying a higher pres- 
sure, it would work against the lower pressure. 

370. Q. What is such a pump used for in ordi- 
nary service? 

A. It can be used to force water against a pres- 
sure that is considerably less than the boiler pressure. 
It would be suitable for an elevated tank that is very 
high above the boiler. 

371. Q. Would a boiler-feed pump force water 
into such a tank? 

A. Yes. 

372. Q. Then why not use one for this purpose? 

A. If a 14 by 7 by 12 inch pump, or any corre- 
sponding combination, is used to force water into a 
tank, the steam must be throttled to a very low pres- 
sure, which is not economical. 

373. Q. If both pistons are of equal diameter, 
what is the result? 

A. The steam is used at higher pressure, hence 
under more economical conditions. 

374. Q. What point might be mentioned in favor 
of using a regular boiler feeder for this service? 

A. In case the boiler-feed pump should be dis- 
abled, the tank pump might be used to prevent the 
plant from shutting down. 

375. Q. Is the water piston ever made larger 
than the steam piston? 

A. Yes ; Fig. 65 illustrates an 8 by 14 by 12 inch 
pump. 

376. Q. For what service is such a pump suit- 
able? 

A. To elevate water into a tank at ordinary height, 



PUMPS AND PUMPING MACHINERY. 105 

where a comparatively high steam pressure is avail- 
able. 

377. Q. What is the advantage of such a com- 
bination? 

A. It uses steam under favorable conditions. 

378. Q. Could it be used for fire service? 

A. It would not be worth much to extinguish a 
fire, as a high water pressure could not be secured 
from it. 



& 



379. Q. What combination of steam and water 
cylinder is suitable for fire service? 

A. The same as for boiler feeding, in which the 
steam cylinder is about tw r ice the diameter of the water 
cylinder. 

380. Q. How is a very high water pressure 
secured for hydraulic riveting and similar work? 

A. By using a very large steam cylinder in com- 
parison with the water piston or plunger. 



381. Q. Give an illustration of this kind of 
pump. 

A. Fig. 66 is a 14 by 2y 2 by 12 inch combination 
in which steam acts on 153.9 square inches of surface, 

8 



106 QUESTIONS AND ANSWERS ON 



and as only 4.9 square inches are exposed to water 
pressure, the difference is very great. 

382. O. What is the ratio in this case? 
A. 3fto 1. 

383. Q. How is it determined? 
A. By dividing 153.9 by 4.9. 

384. Q. What is meant by a piston pump? 

A. It is illustrated in Fig. 67. It consists of a 
water piston working in a cylinder. This piston is 




fr//////////^/////^^^^ 



FIG, 67. 



PUMPS AND PUMPING MACHINERY. 107 

usually packed with fibrous packing, but sometimes 
brass packing rings are used. 

385. Q. Why is fibrous packing used? 

A. Because it does not wear the brass cylinder 
rapidly, and when worn out it can easily be replaced. 

386. Q. Name another feature of this pump. 

A. It is called a submerged piston pump, because 
both suction and discharge valves are above the piston. 

387. Q. What advantage is secured by this 
arrangement? 

A. The piston is always under water, hence it 
will secure a high vacuum in the suction pipe, thus 
enabling it to lift water 25 feet or more. 

388. Q. What is a plunger and ring pump? 

A. This type is illustrated in Fig. 68. Instead of 
a regular water cylinder, a ring is used. The illus- 
tration shows a long ring, which is practically a cylin- 
der, but in some cases this ring is much shorter. With 
a short ring it is necessary to use a long plunger, but 
in this case a packed plunger is substituted. 

389. Q. Is the plunger submerged? 

A. No; the suction valves are below the water 
piston or plunger. 

390. Q. Is this type suitable for a high lift, or a 
long suction pipe? 

A. No; it is not designed for such service, but is 
more suitable for a low lift, or where water flows to 
the pump. 

391. Q. Is it possible to make such a pump oper- 
ate on a medium or high lift? 

A. It may not be impossible, but it is imprac- 
ticable. 

392. Q. What advantage is secured by this type? 

A. The water passages are short and direct, there- 
fore friction of water as it passes through the pump is 
reduced to the lowest point. 



108 QUESTIONS AND ANSWERS ON 



393. Q. Describe an outside center-packed 
plunger pump. 

A. It is illustrated in Fig. 69. The piston rod 
carries a long plunger instead of a water piston. This 
works through two stuffing-boxes that are located 




FIG. 6 8. 



PUMPS AND PUMPING MACHINERY. 109 

near the center, hence they are termed " center- 
packed. " 

394. Q. Describe its operation. 

A. The plunger is moving from right to left hand, 
hence the right-hand suction valve is open, and the 
left-hand discharge valve for the passage of water? 



I ! 








QttZZZZZZZZZZZZZZZ 



ZeZZZ2ZZZZZZZZZZ2ZZZZZZZZZZZZZZ22bg- 



Fie. 6 9. 



395. Q. Is this a double-acting pump? 

A. Yes ; when the plunger moves in the opposite 
direction, the left-hand suction and the right-hand 
discharge valve will open for the passage of w r ater. 

396. Q. Describe an outside end-packed plunger 
pump. 



110 QUESTIONS AND ANSWERS ON 

A. It is illustrated in Fig. 70, but all connections 
are omitted, to avoid a complicated appearance. There 
are two separate plungers, which are connected by 
outside rods, hence they move as one plunger. They 
are assumed to be moving from right to left, there- 
fore water is drawn in by the left-hand plunger 
through the circular passage above it, and is going out 
from the right hand, through a passage, the outside 
of which is shown in the illustration. 

397. Q. Where are the stuffing-boxes located? 
A. At the ends of the main body, hence it is called 

" end-packed." 

398. Q. What name is applied to the valve 
arrangement of these pumps? 

A. They are called valve pots. 

399. Q. What are the advantages of outside- 
packed plunger pumps? 

A. Dirty water can be pumped by them with less 
danger of injury than with piston pumps. If they leak, 
it shows on the outside, thus informing the engineer 
of small defects before they become large ones. 

400. Q. What are the disadvantages of this type ? 

A. There are none, except that they require a com- 
paratively large floor space, which is not a serious 
matter. 

401. Q. What kind of pumps are properly classed 
under the head of " Special Single Pumps "? 

A. Pumps that are fitted with one steam cylinder 
only, and are made in some special form for regular 
duty, such as boiler feeding and similar service, and 
those of unique design that are intended for special 
service. 

402. Q. Name a pump of this class. 

A. Fig. 71 illustrates a long-stroke pump. It is so 
called because the stroke is much longer than is given 
to a regular pump. 



PUMPS AND PUMPING MACHINERY. Ill 




tD DDL 



112 QUESTIONS AND ANSWERS ON 



EL* 




PUMPS AND PUMPING MACHINERY. 113 

403. Q. What advantage is gained by this de- 
sign? 

A. The number of times that motion is reversed 
is less for a given piston speed per minute. 

404. Q. Why is this desirable? 

A. The shocks and jars and much of the wear on 
a pump is caused by the reversal of motion at the end 
of every stroke, hence a reduction of these reversals 
results in quiet action and durability of the parts. 

405. Q. Illustrate the result in practice. 

A. Take a piston speed of 100 feet, or 1,200 inches 
per minute. The stroke of this pump is 33 inches; 
therefore, by dividing 1,200 by 33 we find that it will 
make 36 strokes and be reversed 36 times per minute. 
If the stroke were but 12 inches, it would make 1,200 -=- 
12 = 100 strokes, or nearly three times as many as the 
long-stroke pump. 

406. Q. What are the disadvantages of this 
pump? 

A. It occupies more space than a short-stroke 
pump of the same general type, but this is not a serious 
objection. The stuffing-boxes are so close together 
that the middle of the piston rod goes into the steam 
cylinder and the water cylinder alternately, and is 
thus heated and cooled many times per minute. The 
first cost of such a pump is greater than for a short- 
stroke type. 

407. Q. When all points are considered, is the bal- 
ance in favor of or against the long-stroke pump ? 

A. Decidedly in favor of it. 

408. Q. Then why is it not more extensively 
used? 

A. Because its greater capacity at a given num- 
ber of strokes per minute, or its superior action at a 
given piston speed, are not taken into proper consid- 
eration in connection with the price quoted. 



114 QUESTIONS AND ANSWERS ON 

409. Q. Name another special pump. 

A. Fig. 72 is a long-stroke pump fitted with a 
combination rod and a long body. This design pre- 
vents the middle of the rod from entering either cylin- 
der. This rod is made in two pieces and joined at 
the middle as shown. Under some conditions the 
water end of rod wears much faster than the steam 
end. In this case it is only necessary to renew one- 
half of the rod, thus saving expense. 

410. 0. Show still another special pump. 
A. Fig. 73 is a sectionalized mountain pump. 

411. Q. What is its peculiar feature? 

A. It is designed so that when taken apart no 
piece weighs more than 300 pounds. 

412. Q. Explain the advantage of this feature. 
A. Pumps are wanted for use in mines and other 

places in rough and rugged mountains, where it is 
impossible to take a wagon, hence all machinery and 
supplies must be transported on the backs of mules. 
This design makes it possible to " pack " a pump to 
any desired point. 

413. Q. Is such a pump more liable to wear rap- 
idly, or to become separated in service, than one of 
the ordinary kind? 

A. No; great care is taken to guard against such 
mishaps, and they need not be feared if the pump is 
properly assembled, agreeable to the maker's design. 

414. Q. How large a pump is thus designed? 

A. 14 by 6 by 18 inches, weighing more than 3,000 
pounds. 

415. Q. Describe another mine pump. 

A. Fig. 74 is a single, direct-acting pump that is 
fitted w r ith an outside valve gear, but in this case a 
special covering is fitted over the moving parts, hence 
they can not be bent nor broken in transportation. 
They are not easily disarranged by accident or other- 
wise while in service. 



PUMPS AND PUMPING MACHINERY. 115 




116 QUESTIONS AND ANSWERS ON 




io o o 

"I 111 II' 
a o si 



I 








PUMPS AND PUMPING MACHINERY. 117 




I " I 



" ' ' I 




Ef 



3 




118 QUESTIONS AND ANSWERS ON 

416. Q. For what purpose are hydraulic pumps 
used? 

A. Whenever a very high water pressure is re- 
quired. This covers locomotive and car works, pipe 
and tube works, cotton and tobacco pressing, cranes 
and drawbridges. 

417. Q. Describe a pump used in such service. 
A. Fig. 75 shows a 21 by \% by 16 inch hydraulic 

pump that will pump the pressure up to about 12,000 
pounds. 

418. Q. What is the ratio of cylinder to plunger 
in this case? 

A. 125 to 1. 

419. Q. If there is 12,000 pounds pressure per 
square inch on the plunger, how much steam pressure 
on the piston is necessary to balance the water pres- 
sure? 

A. 96 pounds. 

420. Q. How is it determined? 

A. By dividing the water pressure of 12,000 
pounds by the ratio, which is 125. 

421. Q. About how much steam pressure is re- 
quired to move the plunger against this pressure? 

A. 125 pounds would move it slowly, under favor- 
able conditions, but 150 pounds ought to be available 
for good service. 

422. Q. Illustrate and describe another special 
pump. 

A. Fig. 76 is a 12 by 4 by 12 ammonia pump, for 
use in refrigerating and ice-making plants. 

423. Q. How does this differ from a boiler-feed 
pump? 

A. It is made extra strong, to withstand a high 
working pressure. All parts of the pump end are made 
of iron or steel, to withstand the action of this liquid. 
The stuffing-box is made extra long, to hold enough 
packing to prevent leakage at this point. 



PUMPS AND PUMPING MACHINERY. 119 




120 QUESTIONS AND ANSWERS ON 







1 i»'"' L ' J ' .|^ T 



PUMPS AND PUMPING MACHINERY. 121 

424. Q. Why are special precautions taken to 
prevent leakage from such a pump? 

A. Because ammonia is expensive, and it is not 
safe to inhale it even when mixed with air. 

425. Q. Do all parts of an ammonia pump wear 
in about the same proportion as on other pumps? 

A. No; the pump end wears and corrodes faster 
than the steam end, therefore the piston rod is made 
in two parts ; consequently the part that comes in con- 
tact with ammonia can be renewed without disturbing 
the other. 

426. Q. State another purpose for which a spe- 
cial pump is required. 

A. For withdrawing air, steam and water from 
steam-heating systems, thus changing them from low- 
pressure to vacuum systems. A pump of this kind is 
shown in Fig. 77. 



a &. 




FIG. 7 7 



427. Q. How is such a pump connected and used? 

A. The returns from the heating system to be 
operated are all connected into the suction opening. 
When the pump is started, a partial vacuum is created 
in the return pipe, and all water resulting from the 
condensation of steam is withdrawn. 
9 



122 QUESTIONS AND ANSWERS ON 

428. Q. Is this water returned direct to the boiler 
by this pump? 

A. No ; it is delivered to a tank and fed to another 
pump in economical plants, and allowed to waste in 
plants that are not well managed. 

429. Q. Is a high vacuum necessary in this 
service? 

A. No; 8 or 10 inches is usually sufficient. 

430. Q. What are the comparative sizes of cyl- 
inders? 

A. The illustration shows an 8 by 12 by 12 inch 
pump. 

431. Q. What is the effect on the heating sys- 
tem? 

A. When steam is turned into a cold system of 
pipes for heating, the whole is quickly filled with 
steam, owing to the reduced back pressure, conse- 
quently the rooms are heated in less time than when a 
pump is not used. As the pressure is low, a given 
quantity of steam is expanded into a larger volume. 

432. Q. Is there another kind of vacuum pump 
in general use? 

A. Yes ; it is illustrated in Fig. 78. This pump is 
used in sugar refineries, etc., where a high vacuum is 
required. 

433. Q. What is considered a high vacuum? 
A. From 26 to 28 inches. 

434. Q. What is a water seal for a vacuum 
pump? 

A. A pocket in the pump casting is located where 
the piston rod passes through it. When filled with 
water it prevents air from leaking into the pump and 
lowering the vacuum. 

435. Q. What is a magma pump? 

A. It is a pump designed to handle second and 



PUMPS AND PUMPING MACHINERY. 123 



third sugars in refineries, also any thick semi-liquid, 
white lead, etc. See Fig. 79. 

436. O. What are its peculiar features? 

A. The pump passages are large and direct. The 
valves can easily be removed for cleaning, and quickly 
replaced. 

437. Q. Is it practicable to utilize the direct- 
acting principle in operating blowers, or blowing 
engines? 

A. Yes; for certain purposes such machines are 
very satisfactory. Fig. 80 illustrates a 10 by 16 by 18 
direct-acting blowing engine. 

438. O. For what service is this available? 

A. For oil refineries and chemical works, where 
it is necessary to force air at light pressures through 
oils, chemicals and liquids. 

439. Q. Is the action of such a blower steady and 
positive ? 

A. It can not be termed steady, as the air piston 
must be reversed at the end of each stroke, but inas- 
much as air is very elastic, the fluctuation is not 
excessive. The action is positive, for what is drawn 
into the air cylinder on one stroke must be expelled 
on the next. 




?{<&?& 



124 QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. 125 




126 QUESTIONS AND ANSWERS OX 

440. Q. Could such an engine be used for forcing 
fires under steam boilers? 

A. Yes; it would give good results in such 
service. 

441. Q. Why is the air cylinder in this case so 
much larger than the steam cylinder? 

A. In order to move a large volume of air, with a 
comparatively small volume of steam at higher pres- 
sure. 

442. Q. What is the object of this design? 

A. To use steam to the best possible advantage. 

443. Q. Why are these pumps fitted with a valve 
gear, by means of which the length of stroke can be 
varied? 

A. Because it is desirable to make the air piston 
travel as far as possible each stroke, without striking 
the cylinder head. 

444. O. Why is more attention paid to this fea- 
ture in a direct-acting air compressor, or a blowing 
engine, than in a boiler-feed pump? 

A. Because air is elastic, and water is not. 

445. Q. What bearing does this have on the mat- 
ter under consideration? 

A. If the clearance is large in an air compressor, 
or a blowing engine, due to a short stroke of the pis- 
ton, the air in this clearance expands when the motion 
of piston is reversed, and thus prevents outside air 
from entering readily. 

446. Q. What is the effect in practice ? 

A. The capacity of the air compressor is reduced 
and steam is used at a great disadvantage, hence the 
efficiency of such a pump is low. 

447. Q. What is the difference between an air 
compressor and a blowing engine? 

A. The former usually compresses air for use at 
a high pressure, while the latter delivers air at a low 
pressure. 



PUMPS AND PUMPING MACHINERY. 127 

448. Q. With a given size of air cylinder, would 
the steam cylinder be the same in both cases? 

A. This would depend upon the steam pressure 
available. On general principles it would be large for 
the former and small for the latter. This would be 
absolutely necessary if the steam pressure was uni- 
form. 

449. Q. Why are the air cylinders of compress- 
ors water-jacketed? 

A. In order that cold water may be circulated 
around them to prevent the accumulation of heat. 

450. Q. Why is this not necessary on a blowing 
engine? 

A. Because air is not retained in them, but is 
forced directly through the cylinders and passages; 
hence, heat contained in the air passes off with the 
rapid circulation provided. 

451. Q. What is meant by " three-cylinder 
pumps " ? 

A. Pumps in which one steam cylinder operates 
two other cylinders. 

452. Q. What are the objects of building them? 
A. To secure large capacity in small floor space, 

to avoid operating two separate pumps when one is 
sufficient, and to reduce the first cost. 

453. Q. Illustrate and describe one of these 
pumps. 

A. Fig. 81 shows a three-cylinder crank and fly- 
wheel pump, fitted with a throttling governor. 

454. Q. What is the object of this governor? 

A. To prevent excessive speed in case more steam 
is turned on than is sufficient for a slow speed. 

455. Q. What other condition might cause a 
dangerous speed? 

A. The bursting of a delivery pipe, or failure of 
the source of supply of water. Anything that suddenly 
reduces the pressure is dangerous. 



128 QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. 129 

456. Q. Does this prevent running at slow speed? 
A. No. The speed may be regulated by the 

throttle valve, the same as if a governor was not used. 
The governor may be set for different speeds. 

457. Q. What are the advantages of a crank and 
fly-wheel as applied to these pumps? 

A. It insures full stroke of the steam piston, thus 
avoiding waste of steam, by short stroke, and both 
pump pistons give full capacity. 

458. Q. What are the advantages of placing the 
cylinders so far apart on the frame ? 

A. It gives the engineer a chance to pack the 
stuffing boxes, and cylinder heads when required, 
without removing any other part. It avoids running 
the piston rod from a hot into a cold cylinder and vice 
versa. 

459. Q. For what purpose is the middle cylinder 
used? 

A. To elevate cold water, or to force it against 
low pressure. 

460. Q. What name is given to this particular 
pattern of water pump and why is it so called? 

A. It is known as the double-deck pattern because 
each set of valves rests on a separate deck or plate. 

461. Q. What is the other cylinder used for? 

A. To create a high vacuum in sugar pans or for 
other purposes. 

462. Q. What is a three cylinder double-vacuum 
pump? 

A. It is illustrated in Fig. 82. One steam cylinder 
supplies power for two vacuum cylinders operated for 
different purposes. 

463. O. What is meant by a " tail pump " ? 

A. It is illustrated in Fig. 83. A steam cylinder 
supplies power for operating a vacuum cylinder on the 



130 QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. I'M 

same frame. The piston rod is continued through this 
cylinder, and into another that is fastened to the outer 
end of the larger. 

464. Q. For what purpose are these cylinders 
used? 

A. The larger one creates a high vacuum for use 
in manufacturing sugar, and the smaller takes the cane 
juice or syrup. 

465. Q. What other name is given to these small 
pumps? 

A. They are also known as " sweet-water pumps." 




466. Q. Describe another form of combined 
water and vacuum pump ? 

A. Fig. 84 illustrates one of these pumps, showing 
a steam cylinder in the middle, a water cylinder at the 
right, and a vacuum at the left hand. 

467. Q. Give the comparative sizes of pistons in 
this case. 

A. Steam 10 inches, water 5 inches, vacuum 10 
inches, stroke 12 inches. 

468. Q. Why is the water piston comparatively 
small? 

A. To deliver water against a high pressure. 

469. Q. Is this pump designed for the " wet " or 
" dry " vacuum system ? 



132 QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. 133 

A. It will operate either at pleasure. 

470. Q. What is the difference between these two 
systems? 

A. The wet system causes all water used to pass 
through the pump, while the dry system allows it to 
pass off through the leg pipe without going through 
the pump. 

471. Q. Describe a combined air and circulating 
pump. 

A. It is illustrated in Fig. 85. Steam cylinder in 
the middle, air at the right, and circulating at the left 
hand. 




472. Q. What are the comparative sizes of these 
pistons and cylinders? 

A. Steam 10 inches, air 9 inches, circulating 10 
inches, stroke 12 inches. 

473. Q. In what service is this pump extensively 
used? 

A. For operating surface condensers in connec- 
tion with steam engines. 

474. Q. Describe its operation. 

A. The air cylinder creates a partial vacuum in 
the exhaust pipe, while the circulating cylinder sends 



134 QUESTIONS AND ANSWERS ON 

water through the condenser to condense the exhaust 
steam. 

475. Q. Why is the term " partial vacuum " 
used? 

A. Because it is practically impossible to main- 
tain a perfect vacuum. 

476. O. If only a partial vacuum is claimed for 
a condensing apparatus, does it imply that the machin- 
ery is not operating satisfactorily ? 

A. No. It may be giving the best possible results. 

477. Q. Why is a vacuum pump sometimes called 
an air pump? 

A. Because it draws water, steam and air out of 
the cylinder of a steam engine. The name " air pump " 
is convenient to distinguish it from the circulating 
pump, which only keeps water in motion, under a light 
pressure. 

478. Q. Describe another three-cylinder pump. 
A. Fig. 86 illustrates a pump with one steam and 




FlCSfo 



two water cylinders. The right hand is for cold water 
that is pumped into an elevated tank from which the 
condenser is supplied. The left is for hot water taken 



PUMPS AND PUMPING MACHINERY. 135 

from the hot well, or overflow from the condenser, and 
discharged into the cooling tower, or refrigerator. 

479. Q. What provision is made for preventing 
the hot well from being flooded by a surplus of water? 

A. The hot-water cylinder is larger than the cold 
water, hence as both pistons must run at the same 
speed the pump tends to take out more hot water than 
is supplied to the elevated tank. 

480. Q. Are these pumps always of the single 
type? 

A. No. They are frequently of the duplex pat- 
tern, in which case there are six cylinders on one 
frame. 

481. Q. Mention another service to which three- 
cylinder pumps are adapted. 

A. Fig. 87 illustrates a steam cylinder in the cen- 
ter, a salt-water pump at the right, which elevates 
water for cooling purposes where purity is not essen- 
tial, and a boiler-feed pump at the left hand. 

482. Q. What comparative sizes are suitable for 
this service ? 

A. Steam 10 inches, salt water 10 inches, boiler 
feed Ay 2 inches. 

483. Q. Suppose that when running this pump 
fast enough to supply the boiler feed, too much salt 
water is delivered. How can the latter be regulated? 

A. By connecting a comparatively small pipe from 
the discharge into the suction pipe. The amount 
which circulates can be controlled by a valve. 

484. Q. What comparative sizes will give satis- 
factory results? 

A. If the suction is 3 inches the discharge 2y 2 
inches and the circulating pipe Y\ inches it will do 
good work. 

485. Q. Can a three-cylinder pump be operated 
as an aid compressor? 



136 QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. 137 

A. Yes. Fig. 88 shows a steam cylinder in the 
middle, a boiler feeder at the right, and an air com- 
pressor at the left hand. 

486. Q. For what service is this suitable? 

A. It is made in small sizes for automobiles oper- 
ated by steam. It will feed the boiler and maintain 
suitable air pressure on the gasoline tank. 

487. Q. Describe a surface condenser with 
vacuum and circulating pumps. 

A. Fig. 89 illustrates such a combination. The 
vacuum pump is at the right and the circulating pump 
at the left hand. The surface condenser rests upon 
both of these pumps, forming a compact and rigid 
machine. 

488. Q. For what purpose is the vacuum pump 
required? 

A. Steam, from one or more engines, enters the 
central opening at the top, and coming into direct con- 
tact with the large area of cooling surface, is quickly 
condensed. The resulting water is drawn out by the 
vacuum pump, which also removes nearly all atmos- 
pheric pressure. 

489. Q. Describe the operation of the circulating 
pump. 

A. It draws cool water into the lower opening 
shown, and discharges it through the top into the con- 
denser. It is then forced through banks of brass or 
copper tubes of small diameter, until it is discharged 
from the upper outlet shown. 

490. Q. Why must it be pumped in at the 
bottom ? 

A. In order to keep the condenser solidly full of 
water. 

491. Q. Is it practicable to use impure water in 
this service? 

A. Yes, because it does not come in contact with 
exhaust steam. 
10 



138 QUESTIONS AND ANSWERS ON 




00 




PUMPS AND PUMPING MACHINERY. 139 




140 QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. 141 

492. Q. What disposition is made of the pure 
water resulting from the condensation of steam ? 

A. It is pumped back into the boilers. 

493. Q. What is the advantage of this practice? 
A. It provides boiler feed-water that will not form 

scale in the boilers. 

494. Q. What is the disadvantage of it? 

A. Such water frequently causes pitting of the 
tubes and shell which is very dangerous. 

495. Q. Describe still another combination form- 
ing a three-cylinder pump. 

A. Fig. 90 shows a combined wet and dry vacuum 
pumping apparatus, with the dry pump at the right, 
and the wet, in the form of a jet condenser, at the left 
hand. 

496. Q. Why are condensers not always used in 
a steam plant? 

A. Because it is more economical in some cases 
to use the exhaust steam than to condense it. 

497. Q. Give an example illustrating this point. 

A. A mill, shop or factory may be heated by ex- 
haust steam until only a little live steam is wanted, 
but if a condenser disposed of this steam, a large quan- 
tity of live steam would be required. 

498. Q. Would it pay to use a condenser during 
the warm weather of each year? 

A. Yes, provided the exhaust steam can not be 
used for a useful purpose. 

499. Q. How can exhaust steam be used during 
warm weather? 

A. In dye works and other places much water 
must be heated for manufacturing purposes, and all of 
the exhaust steam may be condensed in this service. 

500. Q. If it contains cylinder oil does that ren- 
der it unfit for such use? 

A. Yes, but a separator can be installed which 
will purify the steam. 



142 



QUESTIONS AND ANSWERS ON 



501. Q. For what purpose is a jet condenser 
used? 

A. To create a partial vacuum in the exhaust pipe 
of a steam engine. 




fio9A 



502. Q. Does this refer to the service for which 
a surface condenser is also used ? 

A. Yes. 

503. Q. Explain the operation of a jet condenser. 
A. Fig. 91 is a sectional view of this apparatus, 



PUMPS AND PUMPING MACHINERY. 143 

showing all of the internal parts. Steam from the 
engine enters the condenser through the large open- 
ing facing to the right hand, and water enters through 
the left-hand opening. 

504. Q. How are they brought together? 

A. A large volume of exhaust steam at very low 
pressure fills the condenser, and the cold water is 
sprayed into this steam, which it quickly condenses. 

505. Q. How is this water drawn into the jet 
condenser? 

A. By the action of a pump, which is similar to 
an ordinary cold-water pump. 

506. Q. How is it operated? 

A. By the regular end of a steam pump, which 
resembles the steam cylinder of a light service cold- 
water pump. 

507. Q. Does this cylinder exhaust into the 
atmosphere or into the condenser? 

A. Steam from this cylinder passes into the con- 
denser, thus operating the whole machine under eco- 
nomical conditions. 

508. Q. Is the jet condenser a complicated ma- 
chine? 

A. No; it is the simplest form of this appliance. 

509. Q. Does it pay to install a jet condenser? 
A. There are many plants in which it would 

reduce the coal bill twenty per cent, thus proving a 
paying investment. 

510. Q. What other advantage would be se- 
cured? 

A. If the load is heavy it would probably reduce 
it enough to save the installation of a larger engine. 

511. Q. Why are they not more frequently used? 
A. In some cases the exhaust steam is utilized 

for a good purpose, while in many others the owners 



144 QUESTIONS AND ANSWERS ON 

of steam plants are indifferent to the possible advan- 
tages of such a system. 

512. Q. Are engineers sometimes responsible for 
this condition of affairs? 

A. Yes, because they do not thoroughly under- 
stand the matter and present it in a comprehensive 
manner to their employers. 

513. Q. When are engineers freed from this re- 
sponsibility? 

A. After they have presented all facts and possi- 
bilities in the case in an intelligent and convincing 
manner. 

514. Q. What is the principal condition neces- 
sary to the profitable operation of a condenser, after 
the use of exhaust steam has been considered? 

A. An abundant supply of water available for 
condensing purposes. 

515. Q. About how much water is required? 

A. From twenty to thirty times the amount used 
to feed the boilers. 

516. Q. What conditions affect the quantity re- 
quired ? 

A. The degree of vacuum desired and the tem- 
perature of the condensing water. 

517. Q. Is it possible to operate a condenser 
with a comparatively small quantity of water? 

A. Yes, if a cooling tower, or other means of 
reducing the temperature of water used, is installed. 

518. Q. What objection is found to such an in- 
stallation ? 

A. It increases the complication of a plant, and 
the first cost may be too great to be profitable. 

519. Q. What safety appliance is sometimes used 
on a jet condenser? 

A. A vacuum breaker, as illustrated by the extra 
attachment in Fig. 92. 



PUMPS AND PUMPING MACHINERY. 145 




*,5fc*Fi6.92. 



520. Q. What is the object of this appliance? 
A. It prevents water from being drawn into the 

engine cylinder. 

521. Q. Explain the operation. 

A. A hollow float is provided, and if the water 
rises high enough in the condenser to be dangerous, 
air is admitted to break the vacuum and the engine 
then exhausts into the atmosphere. 

522. Q. Are jet condensers sometimes made in 
more compact form than the foregoing illustrations 
indicate? 

A. Yes; Fig. 93 shows a very compact form of 
jet condenser, applied to a vertical marine engine. 

523. Q. Are air pumps made to operate either a 
jet or a surface condenser? 



146 QUESTIONS AND ANSWERS ON 




ro.93. 



A. Yes ; Fig. 94 shows a vertical, double air pump, 
which can be used with either kind of condenser. 

524. Q. Why is only one vertical steam cylinder 
used? 

A. This particular kind is recommended for com- 
paratively small plants, and the use of one steam 
cylinder large enough to operate both air cylinders 
makes a simple machine from which all unnecessary 
complication is eliminated. 



PUMPS AND PUMPING MACHINERY. 147 

525. Q. Are two steam cylinders sometimes 
used? 

A. Yes; Fig. 95 illustrates a four-cylinder pump, 
consisting of two steam and two air cylinders. 

526. Q. Are all of the cylinders double-acting? 
A. In the two preceding illustrations the steam 



yg €J^9 sa 



fSc 




fig .94. 



148 QUESTIONS AND ANSWERS ON 



cylinders are double, and the air (or water) cylinders 
are single acting. 




Ftc, as. 



PUMPS AND PUMPING MACHINERY. 149 

527. Q. Is it always necessary to use pure water 
in a jet condenser? 

A. No; if a large supply of salt water is availa- 
ble it can be used for condensing purposes, but pure 
water must be used for feeding the boilers. 

528. Q. Is this an economical arrangement? 

A. It is better than to run noncondensing, but it 
is not as economical as if pure water were available. 

529. Q. What causes the difference? 

A. If pure water is available, hot water at from 
110° to 120° is taken from the overflow to feed the 
boilers, thus utilizing some of the heat; but if only 
impure water can be secured, then it must be taken 
at normal temperature and heated before going into 
the boilers. 

530. Q. Is it possible to heat this water by the 
use of heat that would otherwise be wasted ? 

A. Yes ; it can be accomplished by placing a feed- 
water heater between the engine and the condenser. 

531. Q. Can it be heated to the boiling point in 
this way? 

A. Yes, but the boiling point is much lower under 
this condition than if exhaust steam was going directly 
into the atmosphere. 

532. Q. Why is this so? 

A. Because the pressure is lower. 

533. Q. Why is it not always considered advisa- 
ble to install a feed-water heater in connection with a 
condenser? 

A. Because it increases the first cost, and makes 
the plant more complicated in operation. The latter 
objection applies more especially to a condensing 
plant, because it includes more joints to keep perfectly 
tight. 

534. Q. Why are leaks more objectionable on 
a condensing plant? 

A. Because they allow air to be drawn in, thus 



150 QUESTIONS AND ANSWERS ON 

giving no visible evidence to a casual observer of their 
existence. 

535. Q. How should the joints be tested? 

A. By holding a lighted candle near them. If 
there is a leak the flame will be drawn into it. 

536. Q. A surface condenser is usually located 
in a horizontal position. Is this plan always adopted? 

A. No; Fig. 96 shows a vertical surface con- 
denser which is satisfactory in service. 

537. O. What advantage is secured by this plan? 
A. The pumps are more accessible for operation 

and repairs, as they are not covered by the condenser. 

538. Q. Are the pumps always located under a 
horizontal surface condenser? 

A. No ; Fig. 97 illustrates a large horizontal con- 
denser with vertical air and water pumps located 
alongside of the shell. 

539. Q. As each pump is driven by a steam cylin- 
der and piston, how are they operated? 

A. Together they are operated as a duplex steam 
pump. 

540. Q. Can either be operated separately? 

A. No, they can not be separated ; but there is no 
special reason why they should be, for if one is re- 
quired, the other is wanted also, hence if one is dis- 
abled, the other is not available. 

541. Q. Describe another vertical pump that is 
used for several purposes. 

A. Fig. 98 shows a four-cylinder pump which is a 
very compact machine for use in places where the 
floor space is limited. The upper cylinder is operated 
by steam from the boilers. Directly under it is the 
single-acting air pump ; at the left is the double-acting 
circulating pump, while a double-feed pump is at the 
right hand. 



PUMPS AND PUMPING MACHINERY. 151 




152 QUESTIONS AND ANSWERS ON 




PUMPS AND PUMPING MACHINERY. 153 




Fifc.98. 



11 



154 QUESTIONS AND ANSWERS ON 

542. Q. Describe a four-cylinder horizontal pump- 
ing outfit, in connection with a surface condenser. 

A. Fig. 99 shows a boiler-feed pump at the left, 
an air pump next, followed by a steam cylinder and a 
circulating pump, with one piston rod extending 
through all of them. 

543. Q. Illustrate and describe a modern, up-to- 
date steam plant. 

A. Fig. 100 shows the outline of such a plant, the 
main feature of which is a tandem compound engine. 

544. Q. For what purpose does this engine sup- 
ply power? 

A. To operate a vertical ammonia compressor. 

545. Q. How is steam used in this plant? 

A. Most of the piping is omitted for convenience, 
but steam is delivered to the small cylinder, exhausted 
into the larger, and then sent into the large surface 
condenser shown. 

546. Q. What is the tower at the right hand for? 
A. Water from the lower part of this tower is 

taken by one of the pumps and delivered to the top 
of this tower, from whence it trickles back to the bot- 
tom, but the large ventilating fan shown forces air up 
through the water and cools it ; hence when it reaches 
the bottom it is ready for use again. 

547. Q. What is the system of vertical pipes on 
the floor above? 

A. It is an ammonia condenser or cooler. 

548. Q. How is it utilized ? 

A. Another pump takes water from the tower 
base and delivers it to the ammonia condenser, and 
after cooling the ammonia it returns to the lower 
point, then is taken up and cooled. The process is 
repeated indefinitely. 

549. Q. Why is so much machinery required? 

A. For two reasons: (1) Because the best possi- 



PUMPS AXD PUMPING MACHINERY. 155 




156 QUESTIONS AND ANSWERS ON 



'/////y . 






\ jsCj 



^\\\\\\\n\\^N\\^ ^ 




PUMPS AND PUMPING MACHINERY. 157 

ble results are required in order to meet competition 
in selling the product; (2) an abundant supply of 
cooling water is not available, hence the same water 
is used may times over. The loss by evaporation, etc., 
is no more than would be required to feed the boilers 
in a noncondensing plant. 

550. Q. Does such a plant require a more skilled 
engineer than one of more simple design? 

A. It certainly does; therefore, men who expect 
to follow this profession, in order to earn a good liv- 
ing, should not rest until they have mastered every 
detail of such operation, and know how to secure the 
best possible results. Such men are wanted, duly 
appreciated and well paid. 

551. Q. Describe the best way to pump hot 
water resulting from the condensation of steam in 
heating systems back into the boiler. 

A. It should flow or gravitate into a closed re- 
ceiver. It is taken from this by a pump that is con- 
trolled automatically by the amount of water in the 
receiver. This is illustrated in Fig. 101, but the con- 
trolling mechanism is not shown. 

552. Q. What advantage is secured by locating 
the receiver as shown, and taking water from a point 
that is several inches above the bottom of the receiver? 

A. When sediment from the inside of a heating 
system accumulates it settles to the lowest point, and 
as this is below the suction outlet, little or none of it is 
drawn into the pump. 

553. Q. Why is a closed receiver better than an 
open tank? 

A. A closed receiver maintains the pressure car- 
ried on the heating pipes, hence no heat is lost by 
evaporation. With an open tank the pressure is re- 
duced to zero by the gage, with a corresponding reduc- 
tion of temperature. 



158 QUESTIONS AND ANSWERS ON 



554. Q. Is it safe to use a single pump in this 
service? 

A. If the piston will start every time that steam is 
admitted to the steam chest, the result will be satis- 
factory. 




FIO./0/. 



555. Q. Why is it more important to have a 
pump that is positive in action on a receiver than as a 
regular boiler-feeder? 

A. A pump and receiver is usually located in some 
out-of-the-way place where the engineer will not 



PUMPS AND PUMPING MACHINERY. 159 

quickly notice a failure to start, but a regular boiler 
feeder is located in the engine or boiler room, where its 
operation is constantly watched. 

556. Q. What advantage is gained by elevating 
the receiver as shown in Fig. 102? 

A. The hot water flows into the suction chamber 
rapidly and keeps the passages full. It also assists in 
raising the suction valves against the springs which 
hold them down. 




FIG./ 02,, 



557. Q. Why is it necessary to have hot water 
flow into a pump, rather than to lift it more or less 
according to conditions? 

A. If pressure on the surface of hot water is re- 
duced, the boiling point is lowered, hence steam may 



160 QUESTIONS AND ANSWERS ON 

form in the suction pipe, and prevent water from ris- 
ing. 

558. Q. Will sediment pass through such a re- 
ceiver and go into the pump ? 

A. Yes, unless provision is made for preventing it, 
by extending the suction pipe about two inches above 
the bottom of the receiver. 

559. Q. Why is a safety valve attached to a re- 
ceiver as shown in this illustration? 

A. These cast-iron receivers are not intended for 
high pressure, hence if it is increased on the heat- 
ing system above normal conditions the safety valve 
prevents further rise in pressure. 

560. Q. Is a glass gage on a receiver a valuable 
feature ? 

A. If it is always in sight, it would be valuable in 
detecting failure of the pump to take water, but under 
common conditions it is seldom seen, hence is of little 
value. 

561. Q. Fig. 103 shows a receiver located directly 
above the pump. Is this a superior design? 

A. It economizes floor space, and causes water to 
flow freely to the pump, but the receiver is a nuisance 
when the pump must be packed or repaired, therefore 
the design is not superior to others. 

562. Q. Why are receivers sometimes made 
larger in one part than others? 

A. To provide room for the float to rise and fall 
enough to operate the throttle valve. 

563. Q. If a glass gage is provided, is it better to 
locate it in the receiver head as shown in Fig. 104? 

A. Yes, because the connections are less liable to 
fill with sediment and become useless. 

564. Q. Is this receiver set too low for good re- 
sults? 

A. The water level is above the pump valves, 
hence water will flow to them, but the springs ought 



PUMPS AND PUMPING MACHINERY. 161 

to be given light tension, as the head of water to lift 
them is low. On this account the design might be 
criticized, but there is a comparatively large body of 
water in the bottom, where sediment may settle in- 
stead of going into the pump. 




f=iG,/Q3. 



565. Q. Should the inlet always be located at the 
top? 

A. Yes, because incoming water will then fall 
into the body of water already in the receiver, instead 
of running down the sides. 

566. Q. Why is this a valuable feature? 

A. Because water of varying temperature will not 
cause parts of the cast-iron receiver to expand and con- 
tract unevenly enough to be unsafe. 



162 QUESTIONS AND ANSWERS ON 

567. Q. What damage could result from such 
action? 

A. It is possible to crack the receiver. 

568. Q. Is it advisable to put a valve in the suc- 
tion pipe, where the receiver is elevated, as in Fig. 105, 
in order to shut off the water if it becomes necessary 
to repair or pack the pump? 




FIG. f04. 



A. Such a valve would very seldom be used, and it 
might be accidentally closed, when it ought to be open. 
It is better to omit a valve here according to common 
practice. 

569. Q. Where continuous service is necessary, 
should the pump and receiver be in duplicate, so that 
if one is disabled the other could be used? 

A. This is an excellent precaution, but only the 
pump needs to be duplicated, as the receiver will not 
be disabled. See Fig. 106. 



PUMPS AND PUMPING MACHINERY. 163 

570. O. A valve is shown in each suction pipe. 
Is it necessary? 

A. Yes. It is only necessary to use one pump in 
regular service, hence water should be shut off from 
the other. 




FIG/05, 



571. Q. Why are such precautions so frequently 
omitted? 

A. Because the need of them is not always appre- 
ciated until an accident causes annoyance and expense. 
In other cases it is considered of no special trouble to 
shut down the plant for a day or more. 

572. Q. Is this good practice from an engineering 
point of view? 

A. No. Every precaution should be taken to in- 
sure continuous operation. 



164 QUESTIONS AND ANSWERS ON 



573. Q. What objection is sometimes offered 
when a consulting engineer suggests their adoption? 

A. It is claimed that the operating engineer will 
not take proper care of them. 

574. Q. Is this objection sometimes justified? 
A. No. It is true that engineers do not always 

take first-class care of duplicate machinery, but that is 
not a good excuse for not providing sufficient equip- 
ment. 




riG./06, 



575. Q. What precautions should be taken with 
duplicate pumping machinery? 

A. It should always be kept ready for instant use. 
The practice of allowing one machine to remain in a 
damaged condition because it is possible to use an- 
other, can not be too strongly condemned. 



PUMPS AND PUMPING MACHINERY. 165 

576. Q. Should the exhaust steam from receiver 
pumps be discharged into the air or delivered to the 
heating system ? 

A. It should always be delivered to the heating 
system. The practice of exhausting it into the air 
results in the waste of much heat that ought to be 
utilized. 

577. Q. Is it always possible to discharge it 
against the pressure carried on the heating system? 

A. If full boiler pressure is used it is not possible 
to exhaust against it, but this is seldom attempted. In 
a well-designed system from 2 to 5 pounds is sufficient, 
and this resistance is too small for serious considera- 
tion. 

578. Q. What precaution should be taken in this 
connection ? 

A. Care should be taken to prevent cylinder oil 
from going into the heating pipes, and from thence 
into the boilers. 

579. Q. How can this be accomplished? 

A. By installing a separator in the pump exhaust 
pipe, or delivering the steam into the main exhaust 
pipe before it enters the main separator. 

580. Q. If the drip pipes are connected directly 
into the receiver, is there a waste of steam as it goes 
into the pump? 

A. No. Steam does not go into the pump at all. 
Hot water settles to the bottom and is taken by the 
pump. Before this is all used, the float falls, steam is 
shut off and the pump stops. 

581. Q. If the controlling mechanism is not 
properly adjusted, can steam enter the suction pipe? 

A. Yes, but that is not a normal condition, hence 
is an exception to the general rule. 

582. Q. What is the remedy? 

A. The float should be adjusted so that steam will 



166 QUESTIONS AND ANSWERS ON 

be shut off from the pump, before the water level in 
the receiver falls too low. 

583. Q. What effect does steam have when it 
enters the suction pipe? 

A. It causes the pump to pound and run un- 
steadily. 

584. Q. If it is necessary to provide a temporary 
remedy, to keep the plant in operation until the proper 
adjustments can be made, what plan should be 
adopted ? 

A. By admitting cold water the steam will be 
condensed. 

585. Q. Suppose that no provision has been made 
for admitting cold water, then what is the remedy? 

A. The remedy is to connect a cold-water pipe 
into the suction pipe at once. Lack of it is a serious 
defect that should not be tolerated, as it is needed to 
supply the small loss every day that is due to opera- 
tion. 

586. Q. Where a plant is operated by electric 
transmission of power, how is it possible to use a pump 
and receiver? 

A. By providing a power pump that is driven by 
a motor as shown in Fig. 107. A float in the receiver 
operates a switch that turns on current when water 
comes to the pump, and shuts it off at the proper time. 

587. Q. Describe an ordinary portable steam 
pumping outfit. 

A. An upright boiler is mounted on wheels, as 
shown in Fig. 108. A suitable pump is also included, 
and the whole can be moved from place to place as re- 
quired by horses or other draught animals. 

588. Q. For what purposes is such an outfit avail- 
able? 

A. Supplying water for agricultural purposes dur- 
ing dry seasons. Filling tanks for use during the erec- 
tion and preliminary operation of a plant where water 



PUMPS AND PUMPING MACHINERY. 167 

under pressure is not available. Puddling earth filling 
to render it solid and prevent settling afterward. 
Pumping water for use in the manufacture of concrete, 
which is so extensively used in buildings, also for 
pavements. 




Fifc/O/T 



589. Q. Describe a semi-portable steam pumping 
outfit. 

A. It is practically the same as a portable outfit, 
but no running gear is provided. See Fig. 109. It can 



168 QUESTIONS AND ANSWERS ON 

be loaded on a truck and thus moved from place to 
place, but it is not intended for frequent removals. 

590. Q. For what service is it designed? 

A. For filling elevated tanks at railroad stations, 
from which locomotives are supplied. 

591. Q. Why are upright boilers usually adopted? 
A. Because they are light for the amount of power 

developed and occupy but little floor space. 




FIG708. 



592. Q. What other kind of boiler is sometimes 
found in this service? 

A. The locomotive type as illustrated in Fig. 110. 

593. 0. What special advantage is claimed for 
this type of boiler? 

A. None, 



PUMPS AND PUMPING MACHINERY. 169 




12 



FIG./09. 



170 QUESTIONS AND ANSWERS ON 

594. Q. Is it more economical than a vertical 
boiler? 

A. No ; not under normal conditions. 

595. Q. Which will stand the most hard usage 
and neglect? 

A. The vertical boiler. 

596. Q. If a vertical boiler explodes, in which 
direction do the parts move? 




Elggg^ 



FIO.//O. 



A. As a general rule the crown sheet is forced 
downward, sending the shell and tubes upward by re- 
action. 

597. Q. Does a locomotive boiler operate in the 
same way if it fails under pressure? 



PUMPS AND PUMPING MACHINERY. 171 

A. No. There is no rule along this line as the 
results depend on which part fails first. 

598. Q. Is it customary to feed a portable or a 
semiportable boiler by the main pump? 

A. No. An injector is usually provided for this 
service. 

599. Q. What other plan is sometimes adopted 
for this purpose? 

A. A small piston or plunger is operated from the 
main-pump crosshead. It is designed to supply the 
proper amount of water required to feed the boiler. 

600. Q. What are the advantages and disad- 
vantages of this device? 

A. It is reliable in service and durable, but it does 
not supply hot water, therefore an injector is more 
suitable. 

601. Q. What is a single vertical direct-acting 
boiler- feed pump? 

A. A pump fitted with one steam and one water 
cylinder, placed tandem, but one above the other. 

602. Q. Which is usually placed at the highest 
point? 

A. The steam cylinder. See Fig. 111. 

603. Q. How is the steam chest usually located? 
A. At right angles to the steam cylinder. 

604. Q. What is the object of this arrangement? 
A. It prevents the steam valve from falling to the 

lower end of the steam chest by force of gravity. 

605. Q. Does the same force affect the pistons? 
A. Yes; consequently less steam is required on 

the downward stroke. 

606. Q. Does this cause a pump to pound at the 
lower end? 

A. No ; because the valve is given more lead at 
that end, hence the descending piston is cushioned on 
a buffer of steam. 



172 QUESTIONS AND ANSWERS ON 

607. Q. For what other purpose is the valve 
given more lead at this end? 

A. In order that steam may be delivered to the 
lower end more rapidly to raise the parts. 




F»G.//f 



608. Q. Why is this necessary? 
A. When the steam piston is descending, steam 
must be admitted to overcome resistance in the water 



PUMPS AND PUMPING MACHINERY. 173 

pipes, minus the weight of both pistons, the rod, etc. 
When ascending, the same resistance must be over- 
come, plus the above mentioned weight. 

609. O. What advantage is gained by use of a 
vertical direct-acting pump? 

A. It occupies less floor space. 




FIG 112. 



610. Q. Is it possible to adopt a pump that occu- 
pies no floor space at all? 

A. Yes; such a pump can be bolted to the wall of 
a boiler house, the frame of a locomotive, or the bulk- 
head of a vessel. See Fig. 112. 



174 QUESTIONS AND ANSWERS ON 

611. Q. Is it practical to use a vertical duplex 
pump? 

A. Yes; Fig. 113 illustrates one of these pumps, 
which are satisfactory in service. 

612. Q. Describe a vertical sinking pump. 

A. It consists of an approved type of vertical 
direct-acting pump, suspended by iron rods or chains. 
See Fig. 114. 

613. Q. Why is it thus suspended? 

A. In order that it may be raised or lowered at 
pleasure. 

614. Q. For what purpose are such pumps used? 
A. In mines and all other excavations where water 

collects and must be removed. 

615. O. Is it necessary to use any special kind 
of pump in this sendee? 

A. It is not absolutely necessary, but where water 
contains more or less grit and other foreign matter a 
plunger pump is desirable. 

616. Q. If such a pump ought to be made as light 
as possible, in order to facilitate its removal from place 
to place, would it be a good idea to omit the heavy 
air chamber shown? 

A. As this air chamber is used to prevent shocks 
and jars, due to reversing motion of the pump, it ought 
to be retained, because a sinking pump is not firmly 
fastened in place. 

617. Q. Fig. 115 illustrates a large sinking pump, 
fitted with a regular air chamber and a device which 
resembles an inverted chamber. What is this cham- 
ber? 

A. It is a jet condenser. 

618. Q. For what purpose is it used? 

A. To condense the exhaust steam from the steam 
cylinder. 

619. Q. What advantages are gained? 



PUMPS AND PUMPING MACHINERY. 175 




© «E==®===@ 



•ii I 



© - ©===4f= : F=#=^^ 




FK3-II5 



176 QUESTIONS AND ANSWERS ON 

A. The steam is disposed of where it is not a nui- 
sance, and much useless back pressure is removed, 
thus saving fuel. 

620. Q. How is this steam condensed? 




fioii^ 



PUMPS AND PUMPING MACHINERY. 177 



A. It is exhausted into the body of water raised 
by the pump and is quickly changed to water. 

621. Q. Does it heat this water to a high tem- 
perature? 




FiG. i/s 



ITS QUESTIONS AND ANSWERS ON 

A. No; as a general rule it adds but a few degrees. 

622. Q. For what purpose is the three-way cock 
used? 

A. It is located in the exhaust pipes, and is used 
to turn exhaust steam into the air, or send it to the 
condenser at pleasure. 

623. Q. Why is this a good plan? 

A. Because it is a good idea to run the pump non- 
condensing when first started. After it has run a few 
minutes the exhaust steam can be turned into the con- 
denser. 

624. Q. Are sinking pumps always of the single 
type? 

A. No ; the duplex type is adopted for large sizes, 
as illustrated in Fig. 116. 

625. Q. What is a wrecking pump? 

A. It is a pump that is used to raise large quan- 
tities of water and allow it to flow away. See Fig. 117. 

626. Q. Is it necessary to use a special pump for 
this service? 

A. No; any other good pump could be utilized 
with fair results. 

627. Q. Then why is a special design recom- 
mended? 

A. Because it is not expensive for a given capac- 
ity, and it will stand much hard service. 

628. Q. Why is it called a wrecking pump? 

A. Because it is frequently used to remove the 
water from partially submerged wrecks, after the hulls 
have been repaired by divers. Also to remove the 
water from coffer dams. 

629. Q. Is it a single or double acting pump? 

A. It is usually designed to raise water on the 
upward stroke only, hence is a single-acting pump. 

630. Q. For what other purpose is a vertical 
pump used? 



PUMPS AND PUMPING MACHINERY. 179 




29 1L j 



180 QUESTIONS AND ANSWERS ON 




FIG i»7 



PUMPS AND PUMPING MACHINERY. 181 

A. Fig. 118 illustrates a vertical ammonia pump 
which occupies but little floor space. 

631. Q. How is it possible to pump ammonia? 
A. Because it is in liquid form previous to expan- 
sion in a refrigerating system. 

632. Q. Describe the Emerson pump? 

A. The main feature is a pair of large vertical 
receivers, or chambers into which water is lifted by 
the action of steam, which also expels the water and 
delivers it to any required point. One of these is illus- 
trated in Fig. 119. 

633. Q. What causes water to flow into these 
chambers? 

A. Steam is admitted by the globe valve shown at 
the top. This expels the air, after which the valve is 
closed and all steam in the chamber is condensed. As 
this leaves a high vacuum, atmospheric pressure, act- 
ing on the surface of water to be lifted, forces it up 
into the chamber. 

634. Q. How is it forced out? 

A. Steam is again admitted to the chamber and 
the pressure forces it out. 

635. Q. Does this action condense steam rapidly? 
A. More or less is condensed, but the process is 

retarded by a layer of air between steam and water. 

636. Q. What prevents steam, air and water 
from being thoroughly mixed, resulting in water ham- 
mer? 

A. When a body of air is confined between steam 
and water it effectually prevents a mixture until the 
air is allowed to escape. All heating engineers are 
familiar with this fact. 

637. Q. While water is flowing out of one cham- 
ber through the upper check valve shown, what is 
taking place in the other? 

A. Water is flowing into it, thus giving a contin- 
uous discharge. 



182 QUESTIONS AND ANSWERS ON 




FI&./I8 



PUMPS AND PUMPING MACHINERY. 183 



RG.US 



184 QUESTIONS AND ANSWERS ON 

638. Q. How is steam admitted to and shut off 
from these chambers at the proper time to give good 
results? 

A. By a rotary steam valve. 

639. Q. How is this valve operated? 

A. By the small rotary three-cylinder engine, 
shown in Fig. 120. 

640. Q. Does this result in a complicated ma- 
chine that requires special skill and care to operate? 

A. While a good operator is desirable and profit- 
able for any pump made, there is no demand for spe- 
cial skill in this case. 

641. Q. Explain the operation of this engine. 

A. Steam is admitted to all three cylinders, hold- 
ing the pistons in equilibrium, until the exhaust port 
of one is opened, thus destroying the balance and 
causing the engine to rotate as the exhaust ports are 
alternately opened and closed. 

642. Q. How is lost motion at the bearings taken 
up? 

A. There is no lost motion at these points, so far 
as practical operation is concerned, as pressure is 
always applied in the same direction ; hence while 
motion is reversed, lost motion is not taken up. 

643. Q. Is this a high-speed engine? 
A. No; it operates at moderate speed. 

644. Q. What limits the speed of this engine? 
A. The time required to fill the chamber with 

water and to expel the same. 

645. Q. Explain the operation. 

A. When steam is shut off it must remain so until 
a chamber is filled, and when turned on it must not 
be shut off until the water is expelled ; therefore the 
rotary valve must not be operated too fast or too slow 
for this to be done, consequently the speed limit is 
soon reached. 



PUMPS AND PUMPING MACHINERY. 185 

646. Q. How does the speed of this valve com- 
pare with operation of the pump? 

A. Both chambers fill and discharge while the 
valve makes one revolution. 




FIG4ZO 



647. Q. Is the speed of the valve and the engine 
the same? 

A. No ; the engine runs faster than the valve. 

648. Q. Does this engine exhaust into the atmos- 
phere ? 

A. No ; all exhaust steam goes into the chambers 
and is condensed there. 

649. Q. Is it practicable to raise gritty and im- 
pure water with this pump ? 



186 QUESTIONS AND ANSWERS ON 

A. Yes; this pump is well adapted to such serv- 
ice, because none of the moving parts, except the 
valves as they open and close, come in contact with 
the water. 

650. Q. For what places and duties is such a 
pump designed? 

A. For raising water from mines, quarries, sewers, 
and all construction work. For irrigation purposes, 
and wherever a simple machine is wanted, especially 
for continuous service. Of course, it can also be used 
to good advantage where conditions are much more 
favorable, as found in first-class steam plants, for con- 
densers, etc, 



PUMPS AND PUMPING MACHINERY. 187 



INDEX 

PAGE 

Absence of Slip 57 

Advantage of Long Stroke 113 

Advantages and Disadvantages of Geared Pumps. 17 

Advantages of an Endless Belt 16 

Advantages of a Vertical Engine and Pump 20 

Air and Circulating Pumps 133 

Ammonia Pumps 121 

Balance Wheels 86 

Balancing the Moving Parts 94 

Blowing Engines 123 

Caring for Duplicate Machinery 164 

Changing Speed by a Cone Pulley 10 

Combination Rod Pumps 114 

Compound Pumps 72 

Conoidal Pumps 68 

Controlling Supply of Water by a Balanced Valve. 8 

Crank and Fly-wheel Pumps 83 

Definition of the Word " Pump " 1 

Description of a Differential Plunger 29 

Description of a Plunger 18 

Determining the Possible Lift 23 

Determining the Stroke of a Pump 43 

Drawing vs. Forcing Water Through a Heater. . . 6 

Duplex Strainers 83 

Effect of Adding a Third Gear 36 

Effect of Closed Valve 68 

Effect of Increased Speed 27 

Effect of Steam in the Suction Pipe. . 166 

Efficient Fire Pumps 51 

Elasticity and Weight of Water 39 

Failure to Deliver Full Capacity to Boiler 7 

Feeding a Portable Boiler 171 



188 QUESTIONS AXD ANSWERS ON 

PAGE 

Feed-water Heaters with Condensing Engine 149 

Four-cylinder Pump 150 

Height of Lift for a Pump 22 

Horizontal and Vertical Centrifugal Pumps 65 

Hot Water Flowing to Pump 159 

Hydraulic Pumps 118 

Increasing the Water Supply 11 

Intermittent Boiler Feeding 10 

Jet Condenser for a Sinking Pump 174 

Locating Air Leaks 150 

Locating the Discharge Pipe Into a Tank 14 

Location of Steam Chest 171 

Long Sweeps and 45° Ells 14 

Magma Pumps 122 

Maximum Density of Water 39 

Meaning of the Term " Vacuum Pump " 46 

Modern Ice Plant 154 

Operating a Direct Steam Pump 184 

Operation of a Belt-driven Power Pump 8 

Operation of a Jet Condenser 143 

Operation of a Pump Governor 91 

Operation of a Rotary Pump 48 

Operation of Centrifugal Pumps 61 

Operation of Direct-acting Pumps 103 

Operation of Plunger Pumps 109 

Operation of Vertical Pumps 172 

Original Direct-acting Pumps 99 

Packing a Plunger 18 

Partial Vacuum 134 

Perfect Conditions for Pump Operation 25 

Piston Pumps 106 

Plunger and Ring Pumps 107 

Popular Boiler Feeder 99 

Portable Pumping Plants 166 

Power Required to Drive a Pump 12 

Pressure and Friction of a Column of Water 14 

Priming Pumps 82 



PUMPS AND PUMPING MACHINERY. 189 

PAGE 

Pumping Ammonia 181 

Pumping Hot Water 6 

Pumps for Water Containing Sand, Etc 51 

Quadruple Pumps 75 

Quantity of Water Required for a Condenser. . . . 144 

Regulating the Delivery of Water 4 

Regulating the Supply by a By-pass 10 

Reliability in Operation 1 

Removing Oil from Steam 141 

Result of Friction 2 

Returning Condensed Steam to Boilers 157 

Right and Left Hand Pumps 67 

Running a Pump in Either Direction 34 

Safety Valve on Receiver \ 160 

Sending Exhaust Steam to the Heating System. . . 165 

Setting Cranks at Right Angles 40 

Simple Design of Pumps 1 

Simplest Form for Boiler Feeding 2 

Single-acting Pump Delivers a Steady Stream. ... 28 

Single and Double Suction Pumps 63 

Single and Duplex Pumps 99 

Single and Twin Pumps 69 

Sinking Pumps 174 

Slip of a Pump , 57 

Special Pumps 110 

Starting a Centrifugal Pump 78 

Steamheating Pumps 121 

Strainer on a Suction Pipe 8 

Tail Pumps 129 

The Scotch Yoke 80 

Three-cylinder Pumps 127 

Triple Pumps 7S 

Turbine Pumps 71 

Two-stage Pumps 72 

Utilizing Water from the Hot Well 140 

Vacuum Breaker 144 

Variations in Weight of the Atmosphere 23 



190 PUMPS AND PUMPING MACHINERY. 

PAGE 

Vertical and Horizontal Power Pumps 32 

Vertical Direct-connected Pump 2 

Volute Pumps 71 

Wet and Dry Vacuum 131 

What Is a Force Pump ? 47 

Wrecking Pump 178 






FEB 17 1913 



